My mathematical approach to punnet square calculations for multiple morph pairings.

We all know that figuring out the odds for any specific outcome in a multi-morph project can be difficult at best. I've devised the following method to calculate the odds:

First off, look at each morph separately. It's much easier to run a punnet square on one morph at a time then combine back later.

Only concern yourself with phenotypic outcomes,

For example, the following, semi complicated, cross:

Sunglow het anery (one hypo gene, two albino genes and one anery gene) mated to:
TH moonglow (one each hypo, albino and anery genes)

Would be divided into three morph calculations:

Hypo = het x het (dominant)
¾ hypo (possible super)
¼ normal

Albino = Homozygous x het (recessive)
½ albino
½ het albino

Anery = het x het (recessive)
¼ anery
¾ pos het anery

For any multi-morph pairing the total number of possible phenotypes is determined by multiplying the individual morph phenotypes. In the example 2x2x2=8

List out the various possible phenotypes:

Hypo(pos super), albino, anery
Hypo(pos super), albino, pos het anery
Hypo(pos super), het albino, anery
Hypo(pos super), het albino, pos het anery
Normal, albino, anery (note: I listed the "normal outcome for the hypo pairing)
Normal, albino, pos het anery
Normal, het albino, anery
Normal, het albino, pos het anery

Then multiply together the individual phenotype fractions:

Hypo(pos super)(¾), albino(½), anery(¼) = ¾ x ½ x ¼ = 3/32
Hypo(pos super), albino, pos het anery = ¾ x ½ x ¾ = 9/32
Hypo(pos super), het albino, anery = ¾ x ½ x ¼ = 3/32
Hypo(pos super), het albino, pos het anery = ¾ x ½ x ¾ = 9/32
Normal, albino, = ¼ x ½ x ¼ = 1/32
Normal, albino, pos het anery = ¼ x ½ x ¾ = 3/32
Normal, het albino, anery = ¼ x ½ x ¼ = 1/32
Normal, het albino, pos het anery = ¼ x ½ x ¾ = 3/32

Clear as mud?
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Thanks,


Dave Colling

www.rainbows-r-us-reptiles.com



0.1 Wife (WC and still very fiesty)
0.2 kids (CBB, a big part of our selective breeding program)

LOL, to many snakes to list, last count:
21.29 BRB
19.19 BCI
And those are only the breeders

lots.lots.lots feeder mice and rats

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