Talk:Mendelian inheritance

Older discussion

Could somebody with a better knowledge of genetics correct this sentence?

Mendel based theory on they could be both cross-pollinated between two plants or self-pollenated with just one.

silsor 04:49, Jan 23, 2004 (UTC)

Done, I think this what the author meant to say. --Lexor|Talk 10:30, 23 Feb 2004 (UTC)

---

Moved this from the article, I think most of this is already covered in the article and other didn't realize that this kind of information belongs in Talk, but I haven't checked closely. --Lexor|Talk 10:25, 23 Feb 2004 (UTC)

The parts of the previous version I didn't merge. Someone please have another look.

Mendel's First Law: Each adult pea plant has two genes - a gene pair - for each characteristic. The two members of each gene pair separate (segregate) randomly into the eggs or sperm of the plant, so that each egg or sperm contains only one member of each gene pair. The offspring therefore inherits one randomly selected gene from each parent for each characteristic.

The first law of Mendelian Genetics was easily illustrated due to the phenomenon of dominance. Certain characteristics, such as yellow seeds, were found to be "dominant" over other "recessive" characteristics, in this case over green seeds. A yellow-seeded plant crossed with a green-seeded plant produced offspring that were entirely yellow-seeded. However, when these yellow-seeded offspring were crossed with the original green-seeded parent strain (a procedure known as back-crossing), half of the plants in the second offspring generation bore yellow seeds and half bore green seeds. The following diagram illustrates these crossesdominant yellow characteristic and a lower-case y to indicate the recessive green characteristic. These two variants are called alleles of the gene.

YY X yy Parental generation (P)

| V Yy First generation of offspring (F1) All seeds are yellow (Y allele is dominant)

Yy X yy Second cross, F1 with green P | V Yy and yy Second generation of offspring (F2), with an equal proportion of Yy and yy

Mendel's Second Law: During the formation of sperm and egg, the segregation of alleles for one gene is independent of the segregation of alleles for another gene. This law was slightly more complex to demonstrate, requiring the statistical analysis of offspring of plants that differed in two separate characteristics. typing hands getting tired, put this demo in later

Figure

A simpler figure of a dihybrid cross can be found at Dihybrid_cross. neffk 16:24, 18 August 2006 (UTC)

Order of article?

When I came across this article, I found it rather counter-intuitive, in that Mendel's second law comes before the law of segregation, which I believe is his first. Is there a reason I'm missing for this order? The one I can think of is that the law of independent assortment (the second law) is linked to metaphase I, which comes before anaphase I in meiosis. But in my AP Biology textbook, Biology, the law of segregation precedes the law of independent assortment. Auricfuzz 01:19, Jan 19, 2005 (UTC)

I too was confused by that, and I support the reordering of these parts of the article so that Mendel's First Law comes before his Second Law. — Brim 02:36, Jan 19, 2005 (UTC)

Have changed it. AndyZ 16:26, 19 November 2005 (UTC)

Scrambled text

If the two alleles differ, then one, the dominant allele, is fully expressed in the organism's appearance; the other, the segregate during gamete production.

The above sentence doesn't make sense. I looked through the article's history and found this old version which shows that the sentence was created by splicing two pre-existing sentences and leaving out the bit in the middle. Sorry I can't fix it myself, but I don't understand the subject well enough (that's why I'm reading the article) and would probably make it worse. --Heron 19:24, 28 May 2005 (UTC)

I have fixed it; it might have been an accidental deletion. AndyZ 16:24, 19 November 2005 (UTC)

Symbols for Recessive and Dominant?

I was taught that the symbols for a recessive and a dominant trait are always the same letter, except one is capitol and one is lower case. I.e. a red flower would be symbolised as 'R', while the white flower it was being breeded with would be 'r'. Here, they are each being represented by thier individual letters. Is this correct? Was I taught wrong, or are both accepted? Thanks Poisonouslizzie 02:38, 18 November 2005 (UTC)

The normal convention is to use the same letter for both, with the dominant being represented by the capital, and the recessive by the lower case.Humpelfluch

I was also taught to write it that way; it is generally easier to use upper and lower case letters just because it is easier to see which is dominant and recessive. However, it can also be written w/ different letters, as in used in the image. This becomes important after dealing with traits that can have more than 2 alleles, for example see Blood type. AndyZ 01:19, 3 January 2006 (UTC)

The convention is to use a capital for dominant and the lowercase for recessive, both with the same letter. The letter, however, represents the recessive characteristic i.e. a flower that has a dominant red gene and a recessive white gene: the heterozygous genotype would be Ww not Rr. Dallas 06:56, 16 August 2006 (UTC)

The only time you are going to have two different letters will be when there is codominance and you have two traits being shown at once.

Reorganization

This article needs a lot of work. While all the information is there, it is repetitive and disorganized. In addition, some of what is describes is non-Mendelian. Let's see if we can get this thing worked up to a great article!

Parts to Mendelian inheritance

The first problem is the organization of the material. It seems to list Three "Laws." I quickly used "Mendel's Second Law" in a google search and came up with several different answers. Unfortunately, this means that the numbering for Mendel's Laws are quite suspect. However we want to organize it, there are five parts to Mendel's Laws, and each one was an important divergence from the common theories for inheritance at the time:

1. Characters are unitary. That is, they are discrete (purple vs. white, tall vs. dwarf).
2. Genetic characteristics have alternate forms, each inherited from the two parents. Today, we call these alleles.
3. One allele is dominant over the other (Concept of Dominance). The phenotype reflects the dominant allele.
4. Gametes are created by random segregation. Heterozygotic individuals produce gametes with an equal frequency of the two alleles.
5. Different traits have independent assortment. In modern terms, genes are unlinked.

Now, how do we want these? I've seen them call Mendel's Laws, Mendel's Hypotheses, and Mendelian Principles. There are probably others. Some of the google results combined the first three principles into Mendel's First Law; Others combined the first four into Mendel's First Law.

I'm inclined to use Mendel's Five Principles or Mendel's Five Laws, and spell it out in gory detail.

Is there any preference? Or discussion of where we should go? Ted 03:38, 19 May 2006 (UTC) (Signing late)

After thinking about this and looking at various sources, I think the best way to proceed is to talk about Mendel's Five Principles, and correlate them with "Mendel's Laws" in all their messy glory. Are there really no comments? That's hard to believe after all the "discussion" on the various other genetics articles. Ted 07:29, 19 May 2006 (UTC)

Figure numbers

Figures start with fig. 3 and after that fig. 1

I moved the figures into a table so that they would be together and in order. They're a little too big to be put on separate lines. Regarding Figure 2, I'm not that happy with it since the 'short hair' trait seems to be represented by a variation in the color of the bunny. I made a different version of this that I uploaded (Image:Dihybrid cross.png). Unless anyone objects I'll use it to replace Fig. 2. Tocharianne 22:18, 21 December 2006 (UTC)

Well, no one protested so I went ahead and replaced it. (Manx cats rule!) Tocharianne 20:41, 27 December 2006 (UTC)

new section: Mendelian mutations

I added a new section to the article. I would appreciate it if someone else looked over it and makes sure it's okay. Tocharianne 16:55, 21 December 2006 (UTC)

Suggest merge from "Independent assortment"

Perhaps the Independent assortment page should be merged into this page. Segregation already redirects here and I think these topics are best covered together. Dr d12 17:23, 25 February 2007 (UTC)

I agree. -Madeleine 01:16, 28 March 2007 (UTC)

I'm starting to feel ambivalent about this, realizing that "independent assortment" exists in contrast to "genetic linkage". The article includes descriptions of the molecular basis of independent assortment that should not be placed within the mendelian genetics article -- since mendelian genetics was developed and used before a molecular basis was found. (Indeed, it contributed to the discovery of that molecular basis.) - Madeleine 15:34, 22 April 2007 (UTC)

I agree Tocharianne 01:24, 31 March 2007 (UTC)

I agree merge

Law of Dominance?

I've never heard of any law of dominance, and from reading it it just paraphrases part 3 of Mendel's First Law..I suggest we remove it, it's too redundant Out slide 03:40, 13 May 2007 (UTC)

This "law" is also known as "Law of Uniformity". While the "Law of Independent Assortment" refers to the independence of different genes on different loci and how those can be recombined in the offspring (especially in the grandchildren and downwards), the law of uniformity treats the inheritance of a single trait from different homozygotic individuals to their offspring. That some of the writeup is ambiguous may not be an argument for removing the entry... please check your books on elementary biology.

217.210.42.17 (talk) 22:43, 19 January 2008 (UTC)

There is a law of Dominance that states that "in a heterozygous condition when the dominant and recessive alleles are present simultaneously, the phenotype of the organism is determined by the dominant allele and the recessive character is hidden." I am not aware of this being Mendel's own law, but this needs to be included. The other laws are "Law of Segregation" and "Law of Independant Assortmrent". The Law of Dominance is a very important law in genetics. Proquence (talk) 08:40, 26 November 2008 (UTC)

The Law of Dominance is indeed a very important law in genetics. As the Merriam-Webster states, it "proved subsequently to be subject to many limitations: because one of each pair of hereditary units dominates [emphasis added] the other in expression, characters are inherited alternatively on an all-or-nothing basis..." It is also sometimes called Mendel's Third Law, although that could be a subject of debate. This law, however, should not be thrown to the side, but should be at least mentioned in the main article. -Ano-User (talk) 00:41, 20 January 2010 (UTC)

Whaa... who removed the law of dominance?! It's a very important law! Just because we're Wikipedia doesn't mean we can change what is scientifically accepted! Kingsocarso (talk) 17:49, 7 February 2014 (UTC)

Initial acceptance (or not)

The article on Mendel says, "At first Mendel's work was rejected (and it was not widely accepted until after he died)". This article says, "Mendel's results were largely accepted". AFAIK this article is wrong, but I'll leave some time for comment before I change it. Rjm at sleepers 10:30, 14 July 2007 (UTC)

Yeah, that's weird. My understanding is that his original work wasn't accepted or rejected, rather it was ignored because people didn't understand the significance at the time (and because it had a lot of math which biologists weren't used to). The opening paragraph of this article says that when his work was rediscovered it was controversial, but then finally accepted. The History section is a little unclear as to whether his work was accepted or controversial--it probably needs to be clarified. Tocharianne 12:55, 14 July 2007 (UTC)

The strange wording appeared on 10th June, probably as vandalism. I've taken the text back to an earlier version. Rjm at sleepers 10:50, 17 July 2007 (UTC)

PROBLEM WITH ARTICLE: The history section alludes to many details of Mendel's theory/theories that have not been explained up to that point. Could someone please make this article accessible to the lay reader, who is, after all, the reader to whom this article is supposed to be addressed? This is a common problem in science articles. I have seen articles on craters of the moon which do not tell you where the crater is to be found through a telescope, and I have often seen articles on animals that include detailed taxonomies but neglect to mention in what parts of the earth the particular animal in question is to be taxonomized. The root problem here I fear is a certain vanity inherent in swottiness - authors are more concerned with looking clever in front of experts than offering their knowledge to the wider public. They care more about displaying their knowledge to those who already know the material than giving it to those who do not. —Preceding unsigned comment added by 87.192.112.144 (talk) 22:53, 5 September 2008 (UTC)

Vandalization? and other issues.

Someone edited this and put some immature rude stuff in, which amused me because what loser could possibly have a beef with dear old Gregor Mendel? But anyways, this article has some animal-centric language (such as characterizing gametes as specifically egg and sperm, which they are not necessarily, or identifying parents as specifically male or female) which could be done away with. And in some places, this article seems to be more from simple english than regular english, and appears directed at small children. I think it would serve this article well the be completely rewritten by someone extraordinarily knowledgeable about Mendel (with some of the better parts salvaged), instead of some 14 year old kid who heard of him in his biology class. —Preceding unsigned comment added by 65.189.30.239 (talk) 00:54, 1 April 2009 (UTC)

Help in Defining

We have two parent types (of a different species), and the resulting cross is an intermediate for the most part in phenotypes. In terms of Mendelian Genetics, even after many generations, are both parent types manifest in the hybrid population? In other words, will a few rare individuals that resemble each parent be evident as a "throwback", and if so, what is that phenomenon referred to as? Thanks. Ledboots (talk) 15:12, 13 October 2009 (UTC)

Your assumptions seem to be a jumble of blending theory and early twentieth century ideas on racial hierarcies that have little or nothing to do with Mendelianism, though there is a link to the concept of atavism. Paul B (talk) 19:38, 22 October 2009 (UTC)

Cleanup Required

This gem of an excerpt from the independent assortment section:

"mendel also do a experiment.he cross different flowers and as a result 3:1 ratio is Independent assortment occurs during meiosis I in eukaryotic organisms, specifically metaphase I of meiosis, to produce a gamete with a mixture of the organism's maternal and paternal chromosomes."

Haven't had time to read the rest of the article, but clearly this needs to be cleaned up. —Preceding unsigned comment added by 70.179.172.117 (talk) 21:10, 19 October 2009 (UTC)

mendel's view

mendel' —Preceding unsigned comment added by 203.115.174.31 (talk) 09:53, 16 November 2009 (UTC)

Grammar

In the first paragraph, the line: "They were initially derived from the work of Gregor Mendel..." would it be "They" or "It" since it is referring to Mendelian Inheritance, not "Inheritances", right? Melara... (talk) —Preceding undated comment added 23:11, 2 December 2009 (UTC).

Reference #1

In the first reference it says "The Monk in the Garden : The Lostgvnfjvkbn nhjegj g vjf grn vnr g g jkbbn qle fa fealrlb ndk vj g cm kjlkcm m blmvdlc, mlmm cs...ii based myt project on his dumb ass shit... and Found Genius of Gregor Mendel, the Father of Genetics. Houghton Mifflin"

I have a feeling that is not the title of the book. 72.208.36.87 (talk) 23:02, 6 December 2009 (UTC)

Anacronisms

To many terms used in this article are merging ideas from the sinthethic theory of inheritance or cromosomical theory of inheritance. I think that Mendel never uses terms as genetics, homozigosis or F1/F2... So Mendel never ... "summarized his findings in two laws; the Law of Segregation and the Law of Independent Assortment." as it now claims the article. Maybe Tschermak, Correns or De Vries made it or maybe in english papers from Fisher, Bateson, Punnet or Morgan, later. I don't know when the become formally and textually "Laws". So, anyone have the source?--Bestiasonica (talk) 00:10, 12 December 2009 (UTC)

I'd like a verbatim quotation of Mendel's conclusions. What did he claim and in what terms? (And source, please.) Here or in the article on Mendel himself. Tsinfandel (talk) 15:21, 16 July 2011 (UTC)

Description of chromosomal inheritance ignores crossover

Some parts of the page correctly refer to the fact that during crossover the maternal and paternal chromosomes are paired up and mixed to produce new chromosomes for the offspring, but other parts of the page are written as if maternal or paternal chromosomes are passed down unmodified. Clement Cherlin (talk) 01:22, 3 January 2011 (UTC)

Law of Dominance

Just noting that Law of Dominance redirects here, but has still not been incorporated into the text. Danger ^{High voltage!} 17:38, 10 June 2013 (UTC)

Law of Segregation

The Law of Segregation states that every individual possesses a pair of alleles (assuming diploidy) for any particular trait and that each parent passes a randomly selected copy (allele) of only one of these to its offspring. I removed "of only one of these" since you cannot randomly select more or less than one from a pair of alleles. Maniacq (talk) 10:13, 12 February 2014 (UTC)

Numbering of Laws

The Law of independent assortment is generally considered the Third law (sometimes the second), but the law of dominance is considered the first, never the third.--Miguelferig (talk) 17:12, 13 April 2014 (UTC)

Actual Data

This article is missing data that I believe could be important. To start Mendelian used a pure purple and a pure white flower the data is missing on witch color flower was the father and witch one was the mother after this the plants were inbreed so I believe this data would be important in determining if there would be different results with better breeding at the time of this experiment incest was legal but for about three generations now incest has been outlawed in the US and I have seen evidence in my family tree that would contradict Mendelian laws now that incest is outlawed. 2001:558:6012:1B:5CF8:2FED:C347:768E (talk) 21:00, 3 March 2018 (UTC)

I think that's just how your textbook illustrates the concept. ~ Amory (u • t • c) 01:56, 5 March 2018 (UTC)

New Graphics

I made some new graphics easier to understand. They correspond to the plants Mendel used for his experiments. Sciencia58 (talk) 11:15, 30 September 2019 (UTC)

Sciencia58 (talk) 15:34, 30 September 2019 (UTC) Sciencia58 (talk) 11:08, 3 October 2019 (UTC) Sciencia58 (talk) 07:39, 4 October 2019 (UTC)

The Punnet square was not inveted by Gregor Mendel, but by Reginald Punnett. The Punnet square doesn't belong in the introduction about the Mendelian principles as first image. Of course we use it for illustration, but then keeping the correct order of Mendel's discoveries explained. Sciencia58 (talk) 06:39, 4 October 2019 (UTC)

What does the B b mean in the graphic on the left? Dominant alleles are symbolized by an upper case letter, recessive alleles by a lower case letter. But why B? Is that supposed to mean blue? Mendel used purple-red and white blooming plants. In the book Campbell Biology, German edition page 298, a capitol P and a small p stand for purple (dominant) and non-purple (recessive). Now we ended up with blue. What a confusion for the poor students, who are supposed to learn and understand this in context with the other graphic using the letters R and w for red and white, which is correct, but with wrong numbering. The P-generation is not Nr. 1. The F1-generation is not Nr. 2. Yes, both pictures are pretty SVGs but they both only contribute to the never ending confusion. Therefore I made the new technically correct graphics. Sciencia58 (talk) 07:16, 4 October 2019 (UTC)

Law of independant assortment

There are no homozygous Manx cats with the genetic defect for short tail, because homozygosity is lethal and the embryo dies in the womb. Instead we can use this picture with coat colour genetics of cattle as example for independant assortment, as it is very similar to the coat colour genetics of dogs.

Sciencia58 (talk) 11:48, 30 September 2019 (UTC)

Mendelian principles

By the way: Champbell called the rule of segregation the first Mendelian law, which is wrong. In the original German literature the uniformity rule comes first.

The Mendelian inheritance doesn't follow strict "laws". There are exeptions. It would be appropriate to speak of Mendelian rules in English literature as well.

The First Mendelian Rule is the uniformity rule saying that by crossing two different homozygous individuals all offspring in the first generation have the same genotype (heterozygot) and same phenotype (dominant trait).

The Second Mendelian Rule is the rule of segregation saying that by crossing two heterozygous individuals 25 % will be homozygous for one allele, 50 % heterozygous and 25 % homozygous for the other allele.

The Third Mendelian Rule is the rule of independant assortment due to free combinability of genes provided they are not located on the same chromosome.

Sources: Prof. Ulrich Weber: Biologie Oberstufe and many others.

[1] [2] [3]

So there will be a few things to do in this article.

English sources: [4] [5] [6] [7] [8] [9]

It would be also okay to call them Mendelian principles. Sciencia58 (talk) 19:37, 30 September 2019 (UTC)

Redrose Please don't make reverts without reading the discussion and the sources first. Sciencia58 (talk) 07:57, 2 October 2019 (UTC)

The scientific community has agreed to no longer call Mendel's rules "laws" because there are many exceptions that can be explained by the chromosomal theory of inheritance. Mendel's rules are also referred to as rules or principles in English literature. The term laws is wrong and outdated. Sciencia58 (talk) 08:05, 2 October 2019 (UTC)

You should not unilaterally make sweeping changes such as these without first obtaining consensus. Yes, you have proposed your changes here, but that was less than two days ago which is hardly enough tome for others to comment. Did you drop informative notices (in accordance with WP:APPNOTE whilst observing WP:MULTI) at, for example, the talk page of WikiProject Genetics? --Redrose64 🌹 (talk) 08:20, 2 October 2019 (UTC)

In the German Wikipedia there are always many biologists who read new contributions on the discussion pages immediately and answer within a few hours. I have not left any information elsewhere because I do not know these addresses. It would be nice if someone would do that for me.

The original publication of Gregor Mendel is written in German. [10]. At the time, Mendel's conclusions were regarded as laws, since they were repeatedly confirmed in his experimental objects. These were mainly pea plants. However, other experimental objects were missing, such as breeding experiments with many other plant species and animals. Chromosomes had not yet been discovered at that time and nothing was known about linked genes on the same chromosome, crossing over, spontaneous mutations and maternal inheritance through mitochondrial DNA. It would be misleading to speak of laws today. This would give the impression that the basic principles discovered by Mendel were wrong. They are correct, but there are too many exceptions to speak of laws [11]. Sciencia58 (talk) 19:00, 3 October 2019 (UTC)

The picture of intermediate inheritance with the rule of segregation cannot be in the paragraph "Non-Mendelian", because segregation also happens in cases of incomplete dominance.[12] New corrected version of the article: [13] Sciencia58 (talk) 19:00, 3 October 2019 (UTC)

Redrose64 The Wikipedia:WikiProject Molecular Biology/Genetics is about MOLEKULAR biology and MOLEKULAR genetics. At the time of Gregor Mendel nobody knew that molecules that are relevant for inheritance exist. The molecular biologists are not responsible for the article Mendelian inheritance. Mendelian inheritance is part of the classical genetics. What does the text module on top of the article mean? I am a Biology college teacher, I have the expertise improve the article. I have listed valid literature sources. So if anyone has anything against it, please comment here. Sciencia58 (talk) 10:53, 3 October 2019 (UTC)

If you would care to look through the talk page that I linked, you would find the thread Wikipedia talk:WikiProject Molecular Biology/Genetics#Possible project consolidation (and please observe the spelling of the word "molecular"). This shows that a number of related WikiProjects - including WikiProject Genetics - were merged earlier this year. This does not remove the article Mendelian inheritance from their purview, and so they have a right to know what you propose. --Redrose64 🌹 (talk) 20:31, 3 October 2019 (UTC)

TedE, Miguelferig, Bestiasonica and Clement Cherlin Can you please have a look at my suggestions in sections 24 to 26 and at my edits, which were reversed by Redrose64. Would you agree to the article being reset to the corrected version I made? Then we can make a few more edits. I would also prefer the term Mendelian principles. In the German book BIOLOGIE from Campbell and Reece the uniformity of the individuals in the F1-Generation is called the first Mendelian principle on page 295. Without such a F1-Generation a cross of two verifiable heterozygous individuals with a dominant trait wouldn't be possible, so the conclusion that all individuals in the F1-Generation have the same genotype and same phenotyp is the basis for the other conclusions. If no one answers, I'll take that as tacit approval. Sciencia58 (talk) 17:11, 3 October 2019 (UTC)

This edit will not have notified Miguelferig, and this edit will not have notified Bestiasonica or Clement Cherlin. You need to make a new post that includes the user links and your signature, and it all needs to be done in the same edit. More at WP:Echo. --Redrose64 🌹 (talk) 20:44, 3 October 2019 (UTC)

Redrose64 Your reasoning doing the revert that these would be laws shows that you have no idea what this is about. Gregor Mendel has statistically proven regularities in inheritance in his pea plants. The people who interpreted his results then spoke of laws. In the meantime, genetic research has established that the common principles Mendel observed have certain exeptions. Neither Mendel nor today's genetic experts speak of laws. Laws are made by politicians, in the best case by lawyers. They must be obeyed by the citizens. Tell a cat that when it gets kittens it has to follow a law about what its kittens have to look like. No. The natural processes of gamet formation (meiosis) in zygotes and embryos are much more complex. This article Mendelian inheritance is in a bad condition. Hundrets of thousands of students in America, Britain and Australia read this and then get bad grades because they trusted Wikipedia. It is our responsibility to ensure that they can trust Wikipedia. At the moment, many teachers in schools discourage or even forbid students from using Wikipedia. This will not change as long as people who are not studied professionals make decisions here. In the discussion above in the contributions of studied biologists the shortcomings were clearly formulated. They made meaningful proposals. My edits corresponded to that. Sciencia58 (talk) 17:54, 3 October 2019 (UTC)

Do not presume that I "have no idea what this is about". That is WP:NPA. --Redrose64 🌹 (talk) 20:45, 3 October 2019 (UTC)

It is the other way round. I'm giving you an excuse for the wrong statement. Let's have peace and do something useful for the article. Sciencia58 (talk) 21:23, 3 October 2019 (UTC)

Hallo

TedE, Miguelferig, Bestiasonica and Clement Cherlin Can you please have a look at my proposals in sections 24 to 26 and tell your opinion. Sciencia58 (talk) 06:43, 4 October 2019 (UTC)

Oranisation of the article

In the sections we must make a clear distinction between the methodological path Mendel followed in his discoveries and the principles he discovered. If he has not worked with Mirabilis jalapa, but this plant can serve as an example of the principle of segregation, which applies in intermediate inheritance too, we must mention it in the Principles section, not in the Non-Mendel Inheritance section. Sciencia58 (talk) 12:42, 5 October 2019 (UTC)

The text under the inheritance scheme with the three generations (red and white) must be changed. A phenotype cannot be dominant or recessive. In a gene-locus with two or more alleles one allele can be dominant over another and other alleles can be recessive or have a dominance hierarchy (Epistasis). This leads to different phenotypes. But a pea plant with red flowers won't dominate the plant with white flowers. In the human world it seems to be different, but this belongs to the field of social behaviour. Phenotype is not a term for an individual, but for the expression of the physical characteristics that are genetically determined. Thus phenotypes have no interaction. Sciencia58 (talk) 13:31, 5 October 2019 (UTC)

Reworked version

Hallo here is a reworked version of the article: [14]. If you have any further suggestions for improvement, please let me know. Sciencia58 (talk) 21:42, 8 October 2019 (UTC)

Have you informed any WikiProjects (or other noticeboards) yet? --Redrose64 🌹 (talk) 21:50, 8 October 2019 (UTC)

Whom should I inform? Where? Sciencia58 (talk) 23:18, 8 October 2019 (UTC)

I already told you, twice. But to explain again: there are WikiPtoject banner templates at the top of this page. Each one has a phrase "join the discussion". That phrase has a link that takes you to the talk page for the WikiProject concerned. These are where you should send notices. If you want to, you can also drop a notice at WP:VPM. --Redrose64 🌹 (talk) 13:13, 9 October 2019 (UTC)

I have been working in the German Wikipedia for many years correcting biologiy articles and writing some new ones. I don't know the administration system of the english Wikipedia. If you manage this article Mendelian inheritance and know the system, could you please do that for me? Sciencia58 (talk) 08:34, 9 October 2019 (UTC)

Redrose64 Thank you for your advice and your patience. Now I hope I found the right place: [15] Sciencia58 (talk) 16:48, 9 October 2019 (UTC)

Redrose64 Still no answer from anyone. It is possible that the molecular geneticists here in the Wikipedia project do not consider Mendelian inheritance so important in view of the great progress made in the field of molecular genetics, because such knowledge is part of the simplest basic knowledge for them, so that they are not interested in dealing with such trivial things. The importance of the article for college students does not seem to them to be a reason. If I don't get any feedback by next week, I'll assume tacit agreement. I have sufficiently justified my proposals for changes and have completed the article Non-Mendelian inheritance in such a way that the own section Non-Mendelian here, which is overflowing with content, can be shortened. Sciencia58 (talk) 06:28, 17 October 2019 (UTC)

Or maybe you posted in low-visibility places. I've found this notice; how many others did you post? I've posted to Wikipedia talk:WikiProject Molecular Biology#Mendelian inheritance and to Wikipedia talk:WikiProject History of Science#Mendelian inheritance. --Redrose64 🌹 (talk) 20:59, 17 October 2019 (UTC)

Hi Sciencia58, I'm glad to see someone working on this article. I've only had a chance to skim the old article and your suggestions so far, but a quick question: In your file File:Intermediate_inheritance_-_incomplete_dominance.png, is the right panel (F1-Generation) intended to begin with heterozygous genotypes? Or am I misunderstanding something? It doesn't seem to make sense as it is now. Thanks for all your work! Sorry for the mostly silence in response to your earlier questions. The biology-interested editors are spread fairly thin on the English Wikipedia. Thanks Redrose64 for posting this more broadly! Ajpolino (talk) 22:13, 17 October 2019 (UTC)

Ajpolino The left panel shows the first cross of two homozygous individuals. The result are heterozygous individuals that cannot produce enough of the pigment, because they have only one allele on which the enzymes for the production of this pigment are coded. In this case that isn't enough. Therefore incomplete dominance. The heterozygous offspring with light pink flowers are all fertile. Of course, crosses can occur between them and these crosses have also been experimentally studied. It was shown that the crossing of two heterozygous individuals results in a phenotype ratio of 1 : 2 : 1. This can be explained by the fact that in the F₂-Generation homozygous are formed again. 50 % heterozygous with the middle color (intermediate), 25 % homozygous for dark pink and 25 % homozygous for white. The genetic test series did not stop after the first generation, otherwise the scientists would not have done justice to the matter. The flower colours of Antirrhinum majus show incomplete dominance as well and follow the same inheritance pattern. So the surprise effect in the F₂-Generation can occur in dominant-recessive inheritances as well as in intermediate inheritances, that homozygous individuals show a trait from a homozygous grand parent. It is important to show that in the inheritance schemes. Otherwise the observer could mistakenly assume that the original colours of the plants of the P-generation would get lost forever with intermediate inheritance and everything would end in a mishmash. This would contradict the finding that these diploid organisms each inherit one of two alleles that meet in the zygote. To understand the arrows in the illustrations, one must look at each flower of the offspring generation and then trace back which allele it received from each parent plant. Sciencia58 (talk) 10:20, 18 October 2019 (UTC)

Sorry perhaps I wasn't clear with my question. In File:Intermediate_inheritance_-_incomplete_dominance.png, the left panel shows heterozygous F1s. The right panel then shows homozygous F1s that mysteriously have the parental genotype but the intermediate phenotype. If one follows the arrows in the right panel, one would get four heterozygotes (like in the left panel). I assumed it was a mistake; but perhaps there's a finer point I'm continuing to miss. To state my question clearly (I hope): in the top-right corner of that image, should the two F1 flowers be shown as heterozygotes? Thanks again for all your time! Ajpolino (talk) 15:36, 18 October 2019 (UTC)

Oh thank you, now I got it. There was a small goofy mistake in the colour of the symbol for one allele. I corrected it immediatly. Sciencia58 (talk) 05:20, 19 October 2019 (UTC)

Please read the revised version of the article. It shouln't remain in a sandbox forever. [16] Sciencia58 (talk) 07:03, 21 October 2019 (UTC)

No more comments? No more objections? Sciencia58 (talk) 06:45, 30 October 2019 (UTC)

TedE can you please read the revised version and give your opinion? Sciencia58 (talk) 10:35, 2 November 2019 (UTC)

Some more content-related inaccuracies

In the section "independant assortment":

1. "There are many violations of independent assortment due to genetic linkage." The statement sounds right, if you beleive the principles were laws. A law can be violated by a person, who doesn't follow that law. If we generally use the word principles, the sentence can be formulated correctly as a statement of facts without criminalizing biological organisms for what happens naturally inside of them: "There are many deviations of the principle of independant assortment due to genetic linkage."

2. "Of the 46 chromosomes in a normal diploid human cell, half are maternally derived (from the mother's egg) and half are paternally derived (from the father's sperm). This occurs as sexual reproduction involves the fusion of two haploid gametes (the egg and sperm) to produce a new organism having the full complement of chromosomes." This sounds confusing, because a haploid cell does have one complete set of chromosomes. So here the formulation must be: "... to produce a zygote and a new organsim, in which every cell has two sets of chromosomes (diploid).

3. "During gametogenesis — the production of new gametes by an adult — the normal complement of 46 chromosomes needs to be halved to 23 to ensure that the resulting haploid gamete can join with another gamete to produce a diploid organism. An error in the number of chromosomes, such as those caused by a diploid gamete joining with a haploid gamete, is termed aneuploidy."

Production of new gamets "by an adult" only applies for men. In humans the development of the egg cells, the meiosis, takes place during early childhood. Every species has its own certain number of chromosomes. Meiosis takes place on both sides during the production of gametes, to avoid that two diploid cells merge during fertilization, not one diploid and one haploid. Aneuploidy is not the topic of this article. This belongs in the article meiosis.

4. "In independent assortment, the chromosomes that result are randomly sorted from all possible maternal and paternal chromosomes. Because zygotes end up with a random mix instead of a pre-defined "set" from either parent, chromosomes are therefore considered assorted independently." Here the way how they segregate is not explained. The gametogenesis in women and men is different, therefore Oogenesis and Spermatogenesis are to be mentioned separately.

5. "As such, the zygote can end up with any combination of paternal or maternal chromosomes. Any of the possible variants of a zygote formed from maternal and paternal chromosomes will occur with equal frequency. For human gametes, with 23 pairs of chromosomes, the number of possibilities is 223 or 8,388,608 possible combinations." Human gametes do not have 23 pairs of chromosomes! This part of the sentence contradicts what has been said before.

6. The zygote will normally end up with 23 chromosomes pairs, but the origin of any particular chromosome will be randomly selected from paternal or maternal chromosomes. This contributes to the genetic variability of progeny." Okay.

7. "Any of the possible variants of a zygote formed from maternal and paternal chromosomes will occur with equal frequency." This is an impermissible generalisation, because in a number of organisms there is a non-accidental segregation of chromosomes [17]. The statements go beyond the scope of this section anyway and there are too many repetitions.

In my reworked version I expressed it more concise. A numbering of the principles, which are still called laws in the new version, is unnecessary. [18]

Sciencia58 (talk) 07:40, 9 October 2019 (UTC)

I intend to outsource most examples of Non-Mendelian inheritance into the appropriate article. I already started to complete it. Examples of Non-Mendelian inheritance don't mean, Mendel generally went wrong. After his discoveries more and more new discoveries about genetics were made. He himself has said that the regularities he discovered apply only to the organisms and characteristics he chose. Sciencia58 (talk) 20:04, 9 October 2019 (UTC)

Please read the revised version of the article. It shouln't remain in a sandbox forever. [19] Sciencia58 (talk) 07:04, 21 October 2019 (UTC)

Vicious circle

I wouldn't be surprised if Campbell or Reece had read the wrong order of Mendel's rules here. This is a common phenomenon today that people use Wikipedia as a source and reproduce content without crediting. Then, in the worst case, we find our own mistakes in the newer literature sources. However, this should not lead us to refer to these sources as a matter of priority, otherwise a vicious circle would develop. Campbell and Reece have also noticed, however, that the uniformity rule is mentioned first in some sources, namely in the original sources. Neil A. Campbell, Jane B. Reece: Biologie. Spektrum-Verlag Heidelberg-Berlin 2003, ISBN 3-8274-1352-4, page 295. Sciencia58 (talk) 07:52, 10 October 2019 (UTC)

Earlier discovery by Huntington

The article on Huntington's#History mentions that Mendel was not the first to describe this principle, although he probably did more thorough research and publicised it. Worth a mention here as well? --Murata (talk) 21:49, 14 June 2021 (UTC)

Huntington published in 1872. Mendel published in 1865-6. The history section refers to the 1900 rediscovery by Hugo de Vries, Carl Correns, and Erich von Tschermak. If there is to be a discussion of this discovery which occurred during the interval, it should should be based on academic sources discussing the relevance. Without such sources, it is a distraction. BiologicalMe (talk) 03:05, 15 June 2021 (UTC)

Gene Expression

• Would adding something on the additional variable that leads to Non-Mendelian Inheritance be a useful addition to that section?

--Eric Lotze (talk) 19:11, 27 March 2023 (UTC)

Not valid 2409:4070:418B:3927:7673:1F4E:6778:8FDC (talk) 10:40, 24 December 2023 (UTC)

Wiki Education assignment: BIOL 412 HONORS

This article is currently the subject of a Wiki Education Foundation-supported course assignment, between 2 February 2024 and 3 May 2024. Further details are available on the course page. Student editor(s): Lhi1001 (article contribs). Peer reviewers: Ard1174, Eliseforget, HabitsofEelz.

— Assignment last updated by Cara.begley (talk) 17:40, 10 March 2024 (UTC)

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Hello, my name is Luke Insana, and I have come to improve the sources linked in the history portion of the article. I also added an inheritance tools section to this article discussing pedigrees and Punnett squares, so that in case a reader had no idea what they were or how to use them, they could learn what they are right here, conveniently within this article. Best,Lhi1001 (talk) 19:04, 23 March 2024 (UTC) Lhi1001