punnet square?

[thegamejr]

i understand how to write out a single gene to single gene, but how would you write out a multi gene to single /other multi gene?

[OhhWatALoser]

I am about to go out for the night but I can make one later, but you need to account for each locus. like lesser pastel x bumblebee, you are going to have LPs, Lps, lPs, lps on one side and lPS, lpS, lPs, lps on the other.

[Daigga]

Biology lesson! Always fun. The only problem with punnet squares and multiple genes is that there get really big really fast.

We'll say dad is a lesser spider, Mom is a mojave pastel. Because random. For this example lesser will be Ll, spider will be Ss, mojave will me Mm, and pastel will be Pp, making dad LlSs and mom MmPp (The smaller letters will represent normals, we know this because neither of the parents is a super in any gene). In a punnet square with multiple genes, you combine the gene combos of the parents (the four variations of dad will be LS, Ls, lS, and ls). After you figure that, it's just filling in the blanks. In this example, the square will be 4x4 with 16 squares. I'm actually doing this weird since we're combining 4 different genes, but as all mentioned genes are dominant or codominate, it doesn't particularly matter if you produce an ss or ll animal, as it will be a normal python without either trait. Plus I don't want a 64 slot table.

	LS	Ls	lS	ls
MP	MLPS	MLPs	MlPS	MlPs
Mp	MLpS	MLps	MlpS	Mlps
mP	mLPS	mLPs	mlPS	mlPs
mp	mLpS	mLps	mlpS	mlps

To read the above table, read anything with a capital letter as a present gene, and anything lower case as normal, keeping in mind that ML will produce a blue eyed leucistic (there, I went and made this complicated). So after a breeding, you will have the chance to produce the following; spider, pastel, spider pastel, lesser, lesser spider, lesser pastel, Lesser spider pastel, Mojave, mojave spider, mojave pastel, mojave spider pastel, Mojave Lesser (blue eyed luecistic, or BEL), BEL spider, BEL pastel, BEL spider pastel, and a totally normal BP. 16 possibilities!

BTW World of ball pythons has a genetic wizard that can figure all of this out for you without the extra work of filling in a punnet square or remembering what each individual morph is called (You've got BELs, queen bees, bumble bees, pastaves, and whatever else in this mix).

Hope this helped!

[thegamejr]

yes that did help, thank you, and i know about both the genetic calculators out there(i use them all the time ha). I just want to have the ability/know how of doing it myself so i can have a better grasp on how the genes are working together, more so a visual. Especially for when i decide to start a recessive project. . . i started doing a bit of research and i cant find too much out there past the basic 101 stuff of the genes

[thegamejr]

So pretty much if you have a 3 gene, for instance a fire bee it would be written out as FfSsPp, and then distributed accordingly on the square? how would that be written out?

[OhhWatALoser]

The one thing I do is make sure every locus is accounted for from the start, so every pair of genes is written down. I find it works better for me since I get things jumbled up. like with the above example, I would of wrote it like this:

	LpS	Lps	lpS	lps
MPs	MLPpSs	MLPpss	MlPpSs	MlPpss
Mps	MLppSs	MLppss	MlppSs	Mlppss
mPs	mLPpSs	mLPpss	mlPpSs	mlPpss
mps	mLppSs	mLppss	mlppSs	mlppss

as far as the firebee, You would start it like this:

FSP

FSp

FsP

fSP

Fsp

fSp

fsP

fsp

[paulh]

http://en.wikipedia.org/wiki/Punnett_square

I prefer the tree method in that reference over the Punnett square method because there is much less addition. To turn a two-gene tree into a three gene tree, do the monohybrid cross for the third gene pair. Take the one to four branch result and put it on the tip of each branch of the two gene tree. Multiply the fractions, and you are done. It takes half the time (or less) than a Punnett square and produces the same result.