So i can narrow it down, exactly what part are you having trouble with? Reading the punnet square or genetics in general?Originally Posted by martyb
A punnet square is easy.
Imagine this is in excel, with clearly defined rows (horizontal) and columns (vertical).
Recessive: A gene that is not “expressed” unless there are two copies. One comes from each parent.
Expressed: What the rat looks like, his Phenotype.
Carries: Recessive genes that the rat has that are not expressed or his Genotype.
The albino locus is defined as "C"
CC = NON albino
Cc = NON albino, but carries the albino gene, but it is not expressed.
cc = Albino, and shows the albino traits.
In the TOP row, you will put the locus of the albino (rat 1). cc is recessive. splitting it into 2 columns
____c____c
In the FIRST column, row 2. you put the locus of the second rat, splitting in half into two rows
C
c
So the top row is rat 1's locus, and column 1 rat 2's locus.
___c___c
C---Cc---Cc
c---cc---cc
In 4 offspring, 2 will be carriers of the albino gene, but not show it and 2 will be true albino.
Make sense yet?
It's difficult when you don't actually see it in a chart.
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