Date

by Mike

Image Text: Well, the kid's definitely getting the biology geek phenotype.

Punnett squares are simple diagrams used to determine the odds of a particular offspring genotype (genetic make up) given the genotypes of the parents.  The phenotype is the physical manifestation of the genes in the organism and doesn't always correlated directly to strict genotypes.  Some genetic characteristics (like color blindness and eye color) can be easily traced using Punnett squares because they are the result of one clearly dominant gene and one clearly recessive.  Other traits like height are a blend of multiple genes.

An interesting thing to note:

The male's parents were both colorblind but that is a recessive gene on the X chromosome.  For his mother to be colorblind she must have had two copies of the gene.  This man now carries the gene on his X chromosome so he will only pass it on to his daughter.  She will be a carrier but will have normal color vision so long as this woman is not colorblind.