how many genes are there?

[scottrussell]

according to this example:
http://www.pitt.edu/~mcs2/herp/genetics.html

if R is red
and B is black
what other traits are there that you throw into the mix?

 

[Serpwidgets]

There are tens of thousands of cornsnake genes. So far, we've identified a handful of them as color/pattern affecting genes:
Amel and Ultra at the albino locus
Hypo
Sunkissed
Lava
Anery
Charcoal
Caramel
Lavender
Motley and Stripe at the motley locus
Diffusion
Pied-sided (Might be at the diffusion locus)
"Z"

There are several other things that might prove out in the near future, too, but the above genes are known to be heritable in typical Mendelian fashion.

 

[paulh]

Nobody knows how many genes there are in corn snakes. The Human Genome Project people estimate that there are 20-25 thousand genes in humans. Corn snakes probably have a number approaching that neighborhood.

The R and B symbols were bad genetics. Apparently the originator was not aware that Bern Bechtel had symbolized amelanistic as a and anerythristic as ax in a paper printed in 1989 in the Journal of Heredity.

Known mutant genes include amelanistic, anerythristic, lavender, lava, sunkissed, hypomelanistic, ultra, charcoal, striped, motley, and a few others. Chuck Pritzel's The Cornsnake Morph Guide (http://www.cornguide.com, I think) has a more complete listing. It is more than worth the purchase price (I own a copy).

 

[scottrussell]

actually, i think what i meant to say is: what are the abbreviations for all of the genes? like if i want to do a punnet square with all of the genes carried with my snakes short of amel and anery i don't know the red of the abbreviations or how to calculate more than 2 genes.

 

[Serpwidgets]

actually, i think what i meant to say is: what are the abbreviations for all of the genes? like if i want to do a punnet square with all of the genes carried with my snakes short of amel and anery i don't know the red of the abbreviations or how to calculate more than 2 genes.

A set of symbols for the currently known genes was published in the Cornsnake Morph Guide, it's summed up on this page: http://cccorns.com/Collection1.php

However, if you are just making a Punnett square to calculate outcomes, use whatever symbols you want. If you use B and b versus A and a for amel, you'll still get the same answer when you cross Bb X Bb as you get when you cross Aa X Aa.

You can use letters, or numbers, or circles and squares and triangles (oh my), or clubs, hearts, diamonds and spades. As long as you are consistent about it so that you can read your answer, it really doesn't matter.

 

[scottrussell]

that's cool. i figured that's pretty much what you do, just wondering if this was a standard. is it possible to have 3 traits in a punnet square? never tried and i pretty much failed high school biology, so im pretty much amazed with myself that i learned this much!

 

[Serpwidgets]

that's cool. i figured that's pretty much what you do, just wondering if this was a standard. is it possible to have 3 traits in a punnet square? never tried and i pretty much failed high school biology, so im pretty much amazed with myself that i learned this much!

Yeah, you can use as many as you want, although the square starts to get insanely huge. In order to fill out the left and top squares, you need to first calculate the possible gametes (sperm and eggs) for the parents, then you just fill them in and go as usual.

At that point, it's easier to multiply the odds out for the particular type(s) you're interested in, which is detailed in the genetics chapter of the CMG. :santa: (And I kinda recapped it in another thread here just a day or two ago.)

But doing 1 and 2 gene Punnetts is very good practice that will help you see the patterns in how things are inherited, so I recommend doing a bunch of them until you're an expert at it... it'll pay off later.