Question

The Manx breed of cats is known for being tailless, though some are born with tails. A dominant gene shortens the spine and is the cause for no tail. In a cross between two tailless Manx cats, you get a litter of kittens where for every 2 tailless kittens, there is 1 kitten with a tail. What happened to Mendel’s 3:1 ratio?

Answer 1

Answer:

When a phenotypic ratio of 2 : 1 is observed, there is probably a lethal allele. Individuals homozygous for the lethal allele do not survive embryonic development, and are not born hence reducing the ratio from 3:1 to 2:1.