In poultry, the genes for rose comb (R) and pea comb (P) produce walnut whenever they occur together (R__ P__);

single-combed individuals have the homozygous condition for both genes (rr pp).
(a) Give the F1 and F2 phenotypic results of a cross of a true-breeding rose comb (RR pp) with a
true-breeding pea comb (rr PP).
(b) Give the phenotypic results of a cross of Rr Pp x rr Pp.
(c) Give the phenotypic results of a cross of RR Pp x rr Pp.
(d) Give the phenotypic results of a cross of Rr pp x rr Pp.
(e) Give the phenotypic results of a cross of Rr Pp x rr pp. What will be an ideal response?


ANSWER: (a) F1: Rr Pp walnut; F2: 9 R__P__ walnut, 3 R__pp rose, 3 rr P__ pea, 1 rr pp single
(b) 3/8 walnut, 3/8 pea, 1/8 rose, 1/8 single
(c) 3/4 walnut, 1/4 rose
(d) 1/4 walnut, 1/4 rose, 1/4 pea, 1/4 single
(e) 1/4 walnut, 1/4 rose, 1/4 pea, 1/4 single

Biology & Microbiology

You might also like to view...

Why do Rh-negative but not Rh-positive mothers sometimes have babies with hemolytic disease of the newborn?

A. This disease results when an Rh-negative mother's immune system is primed multiple times to produce anti-Rh IgG antibodies that can cross the placenta. If the mother is Rh-positive, she won't produce any anti-Rh antibodies at all. B. Rh-positive mothers produce IgM antibody, not IgG. This antibody can't cross the placenta, so it can't cause hemolytic disease of the newborn. C. Rh-positive mothers will receive a preventative shot from their physician prior to conception. This will provide the protection the fetus needs AFTER conception to avoid the disease. D. Rh-negativity is also associated with hyperproduction of antibodies. As such, Rh-negative mothers are more likely than Rh-positive mothers to produce the antibodies needed to produce this disease.

Biology & Microbiology

Systemin can correctly be described as a(n)  

A.  peptide. B.  apoplast. C.  receptor. D.  leaf lipid. E.  carbohydrate.

Biology & Microbiology

Radioactive isotopes have

a. excess electrons. b. excess protons. c. excess neutrons. d. insufficient neutrons. e. insufficient protons

Biology & Microbiology

Which of the following animals lack a "true"

coelom?

a. flatworms only b. annelids only c. roundworms only d. flatworms and annelids e. flatworms and roundworms

Biology & Microbiology