Question

What proportion of the resulting offspring is expected to be male with barred feathers and a pea comb

Answer 1

Assuming diallelic genes that express complete d0minance, 4/16 = 25% of the progeny is expected to be male with barred feathers and a pea comb.

Available data

• Male chickens carry two Z chromosomes.

• Female chickens carry one Z and one W chromosomes.

• The gene for barring is in the Z chromosome.

• The barred trait is d0minant over unbarred trait.

• Gene for comb is aut0s0mic.

• The rose comb is d0minant over the pea comb.

Assuming diallelic genes that express complete d0minance, let us say that

• Barred → Z⁺Z⁺, and Z⁺Z⁻

• Unbarried → Z⁻Z⁻

• Rose comb → RR and Rr

• Pea comb → rr

Cross: unbarred male heter0zyg0us for the rose-comb with a barred female with a single comb.

Parentals)   Z⁻Z⁻ Rr     x    Z⁺W rr

Gametes) Z⁻ R, Z⁻ R, Z⁻ r, Z⁻ r

                Z⁺r, Z⁺r, Wr, Wr

Punnett square)        Z⁻ R             Z⁻ R           Z⁻ r           Z⁻ r

                    Z⁺r       Z⁺Z⁻Rr         Z⁺Z⁻Rr        Z⁺Z⁻rr     Z⁺Z⁻rr

                    Z⁺r       Z⁺Z⁻Rr         Z⁺Z⁻Rr        Z⁺Z⁻rr     Z⁺Z⁻rr

                    Wr        WZ⁻Rr         WZ⁻Rr        WZ⁻rr     WZ⁻rr

                    Wr        WZ⁻Rr         WZ⁻Rr        WZ⁻rr     WZ⁻rr

F1) 4/16 individuals are expected to be males with barred feathers and rose combs, Z⁺Z⁻Rr.

    4/16 individuals are expected to be males with barred feathers and pea combs, Z⁺Z⁻rr.

   4/16 individuals are expected to be females with unbarred feathers and rose combs, WZ⁻Rr.

    4/16 individuals are expected to be females with unbarred feathers and pea combs, WZ⁻rr.

4/16 = 25% of the progeny is expected to be male with barred feathers and a pea comb.

You can learn more about crosses with two genes at

brainly.com/question/4441612