Basic Genetics

[WingedWolfPsion]

*Facepalm*

A) There's nothing wrong with saying "That paper contains incorrect information". It's not rude.
B) Yes, if you're going to continue to complain about it, you SHOULD write your own, and submit it, as obviously you care.
C) If someone says you have incorrect information in your paper, and they are right, you should pull it and correct it, not complain because you put so much work into. Nor should anyone else complain on your behalf.

The point is, the information should be correct, and that is all. My 2 cents.

All the rest is weird social politics that I've never understood, and does not do breeders or the animals any good.

[OhhWatALoser]

The breeding results for codominance and incomplete dominance are the same. Explaining the difference would violate the keep it simple philosophy advocated in this thread.

For what its worth, I have contributed to the Lesson in Basic Genetics sticky. As they are closer to the end than the front, I don't think many people have looked at them.

Calling it co-dominant violates the make it 100% factually and visually correct philosophy.

So far your issue is with the picture, it doesn't even mention the word chromosome, it is on that basic of a level. You respond with a link that starts off with codons and proteins. Which do you honestly think has a better chance of teaching someone, who knows nothing, about inheritance?

[paulh]

Calling it co-dominant violates the make it 100% factually and visually correct philosophy.

100% correctness is impossible in this area because the textbooks do not agree on the definitions of "codominance" and "incomplete dominance". As the breeding results are the same for both, the simplest practical solution for breeders is to lump them together. "Codominant" has the fewest letters of the greater than a dozen possible available terms. This is the solution that the professional mouse geneticists have adopted, but they use the term "semidominant".

[OhhWatALoser]

I've never seen different definitions, incomplete dominant = blending of phenotypes. Codominant = showing both phenotypes. What else says different?

[paulh]

Knight, Jeffrey A. and Robert McClenaghan. Encyclopedia of Genetics. Salem Press, Pasadena, California, USA, 1999. 2 vols.
Zubay, Geoffrey. 1987. Genetics. The Benjamin/Cummings Publishing Co., Menlo Park, CA. 1987, 973 pp. ISBN 0-8053-09100-3

Incomplete dominance occurs when one allele produces a functional product and the other does not. The result is doseage dependent. Two white genes produces white flowers, two red genes produces red flowers, a red gene paired with a white gene produces pink flowers. The functional product is produced only by the red gene.
Codominance occurs when both alleles produce a functional product. As in the A and B blood types. The heterozygous phenotype comes from each gene doing its thing and producing a mixture.
This gives a biochemical basis to separate red, white, and pink flowers from siamese, burmese and tonkinese cats. Pink flowers and tonkinese cats are intermediate between the respective homozygous types. But in tonkinese cats, both genes produce functional products. Robinson's Genetics of the Cat has some material on those cat genes.

[OhhWatALoser]

Incomplete dominance occurs when one allele produces a functional product and the other does not. The result is doseage dependent. Two white genes produces white flowers, two red genes produces red flowers, a red gene paired with a white gene produces pink flowers. The functional product is produced only by the red gene.

how do they come to the conclusion that the phenotype is only because of the red?

[paulh]

Under a microscope, white is the absence of red color.

[OhhWatALoser]

Under a microscope, white is the absence of red color.

But it isn't red or white, it is pink. I don't see how they can say the white isn't doing anything. I could see saying that with a dominant case, the "normal" gene doesn't have an effect if the dominant trait is present and even if there is two the phenotype is the same which is kinda what proves the normal is not having an effect. I don't see how they can define it that way in the white red pink case. Seems to me like the white and red are blending.... you know like the more common definition

[paulh]

I heard somewhere that the heterozygous flower's pigment granules are red under the microscope. Either the pigment granules are fewer in number or smaller or there is some other explanation for the pink color. But all my sources accept the nonfunction of the white gene as common knowledge.

I don't understand the statement about the normal gene not having an effect. The normal gene is for red, and it definitely has an effect. It's just that two red genes have a greater effect than one red gene has.

I think of codominance as being like a black coffee and white milk producing a brown colored mix. Both contribute to the final product's color. Incomplete dominance is more like black coffee and water. They also produce a brown colored mix. But only the coffee contributes color. The water just dilutes that color. If the white flower color gene produced a product, then the pink color would be the result of codominance, not incomplete dominance.

Does a breeder really care whether a blended phenotype in a heterozygous snake comes from two different genes with functional products or from two different genes, only one of which has a functional product?