Question

In cats, the dominant Manx allele produces a cat with no tail. However, the Manx allele is lethal when homozygous. Another gene found on a different autosome affects fur length. Cats that are homozygous for the recessive allele have long fur and heterozygous individuals have short fur.

You cross cats that are heterozygous for both these loci. What are the expected phenotype and proportions of offpspring from this cross? For genotypes, use M/m for the Manx locus and L/l for the fur length locus. Show work.

Answer 1

Given:

Cat with dominant Manx allele= cat with no tail

Manx allele heterozygous = lethal (cat does)

i.e.,, Mm=no tail, MM=cat dies

Homozygous for recessive allele= long fur

Cats heterozygous=short fur

i.e., Ll=short fur, ll=long fur

What is asked to do:

Cross cats heterozygous for both loci

Expected phenotype and proportions of offspring from cross.

Genotype	Proportions	Phenotype
MMLL	1/16	x cat dies x
MmLL	2/16	No tail, short fur
MmLl	4/16	No tail, short fur
mmLL	1/16	tail present, short fur
mmLl	2/16	tail present, short fur
MMll	1/16	x cat dies x
MMLl	2/16	x cat dies x
mmll	1/16	tail present, long fur
Mmll	2/16	No tail long fur

Thanks for the opportunity to answer. Hope this helped.