Question

is the gene that causes tailness in cats dominant or recessive?

show the cross between a manx cat and a normal cat.

find the phenotype and genotype ratio of the F1 generation

Answer 1

The gene that cal tailless in the cats is M = Manx tailless gene (dominant with high penetrance).  Cats with the homozygous genotype (MM) die before birth and Cats with the heterozygous genotype (Mm) show severely shortened tail length, ranging from taillessness to a partial, stumpy tail.

Parents- Mm x mm

tailless cat x normal cat

F1-

	M	m
m	Mm	mm
m	Mm	mm

50% tailles cats with Mm genotype

50% cats with tails i.e normal cats with mm genotype/

PHENOTYPE RATIO = TAILESS : TAILED = 1:1

GENOTYPE RATIO = Mm : mm= 1 : 1