In a cross between a male and female, both heterozygous for sickle cell anaemia gene, what percentage of the progeny will be diseased?
50%
75%
25%
100%
Sickle cell anaemia is an autosomal recessive disorder. Let the normal allele be 'A' and the sickle cell allele be 'a'. Both parents are heterozygous (Aa). The cross is Aa x Aa. The progeny genotypes are AA (25%), Aa (50%), and aa (25%). The diseased progeny are those with genotype 'aa', which is 25%.
Join thousands of students and practice with AI-generated mock tests.