Answer to Question #163092 in Genetics for Mubeen Abbas

Question

Two genes ‘d’ and ‘t’ are assumed to show linkage as well as produce recombinants upto 30%. If dd/ dd individual is crossed with one which is tt/tt. What genotype will produce in first filial generation? Also give the possible meiotic products produced by first generation. If a test cross is performed what phenotypes and genotypes will produced in progeny

Answer 1

The parents produce the following gametes:

Parent 1: dd;

Parent 2: tt.

As a result, the first generation will have the following genotype dd/tt.

The possible meiotic products (gametes) produced by the first generation are:

dd, tt and dt (30 % of gametes).

A test cross is a mating of an unknown genotypic individual with a known homozygous recessive (for example, tt/tt).

In this case, the cross is as follows:

dd/tt × tt/tt

From here, the possible genotypes and phenotypes frequencies of the progeny are:

dd + tt -- > dd/tt (35 %)

tt + tt --> tt/tt (35 %)

dt + tt --> dt/tt (30 %)