Respuesta :
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
https://brainly.com/question/4441612