Answer to Question #266365 in Genetics for mike

Question

A group of researchers studying turtles have isolated an autosomal mutation that confers ninja-like –reflexes just prior to adulthood. This mutation is recessive to the normal slow allele (S). when homozygous slow turtle is mated to a homozygous mutant ninja turtle and the F1 are interbred, the following phenotypes are observed among the F2 young adult: 25 slow, 15 ninjas. Answer the following:

1.      What are the phenotype of the parental generation?

2.      What are the phenotype of the F1 generation?

3.      Perform the Chi-square analysis.

Answer 1

For example, if one parent is homozygous dominant (WW) and the other is homozygous recessive (ww), then all their offspring will be heterozygous (Ww) and possess a widow's peak.

So, the F1 generation all have identical genotypes, heterozygous at the seed color gene