Understanding genetics

[JakesGotSnakes]

So im currently reading a book on ball pythons ive reached the genetics part now ill try to make this short I understand the punnett square for creating an albino simply one option is two heterozygous breeders (Na) now from the outcome of that you "should" come out to one homozygous two heterozygous and one albino of course this is how things are chanced but lets say you wanted to create an albino spider how would that punnett square be created ive wrote out alot of different combinations on paper but can't seem to understand it, I also have been toying around with the genetic wizard off of worldofballpythons but id like to understand the punnett square in general on paper
as always thanks for the help*

[Tsubaki]

First of all, some Punctuation would really help understanding what you are asking. I hope this helps, FYI: Genotype> present genes, Phenotype: visible genes.

Originally Posted by JakesGotSnakes

one option is two heterozygous breeders (Na) now from the outcome of that you "should" come out to one homozygous two heterozygous and one albino

2 Het breeders, so both an genes, a being the albino gene. Would come to produce:
25% aa < Homozygous. (Phenotype Albino, Genotype Albino)
50% na < Hetrozygous. (Phenotype Normal, Genotype Albino/Normal)
25% nn < Homozygous. (Phenotype Normal, Genotype Normal)
Both the an, and the nn are called 66% Het because you can not tell which are which, and you statistically have a 2 out of 3 or 66% chance of the animal having the gene.

So it seems you've got something wrong, since you are talking about both homozygous and albino's as if they are something different. The Albino's and a part of the Normals are Homozygous.

Originally Posted by JakesGotSnakes

say you wanted to create an albino spider how would that punnett square be created ive wrote out alot of different combinations on paper but can't seem to understand it

Spider is a dominant gene.. Not co-dominant, so a Sn will look the same as an SS. Simplest way to breed an albino spider regius would be:

Albino x Spider.

Albino gene does this:
100% na < (Phenotype Normal, Genotype Albino/Normal)

Spider gene does this:
50% Sn< Hetrozygous. (Phenotype Spider, Genotype Spider)
50% nn< Homozygous (Phenotype Normal, Genotype Normal)

Combined that would make:
50% Sn an, (Phenotype Spider, Genotype Spider, Albino)
50% nn an, (Phenotype Normal, Genotype Albino)
__________________________________________________ ________

If you then breed the Snan (Spider het. albino) to each other Snan ^ Snan you get 16 possible genetic combo's since both parents have 4 genes to take into account. (Don't forget to count the normal twice, since they have both a Spider^Normal and a Albino^Normal gene.)

56,25% Spiders (66% poss Alb.) (Of which, 18,75% Homozygous Spider)
18.75% Albino Spiders (Of which 6.25% homozygous Spider)
18.75% Normals (66% poss Alb)
6.25% Albino's

If you would make a punnett square it should look like this:



Hope this helped