Penetrance In a certain breed of plants, thorns are determined by the dominant allele T and thornless is determined by the recessive allele t. T is 60% penetrant in the heterozygote; 40% of heterozygotes will appear thornless. If you make the parental cross TT x tt; what would be the expected number of progeny for each phenotype in a population of 400 F2 plants?

The Thorn plants will be about 300 while the thornless plants will be about 100.

Explanation:

When the parents cross

TT x tt

F1; Tt, Tt,Tt, Tt.

Tt x Tt

F2;. TT, Tt, Tt, tt..

Phenotypic ratio; 3:1.

Hence,3/4* 400=300

1/4*. 400=100

the aswer is letter c

hi~~

i would say that hybridization occurs frequently in nature, because there are many types of hybrids that have occurred naturally, such as the mule (male donkey + female horse)