In horses, black color(B) dominates chestnut color(b). The trotting gait(T) dominates the pacing gait (t). A cross is made between a horse homozygous for black color and the pacing gait and a horse homozygous for chestnut color and the trotting gait.

a. List the probable genotype and phenotype of offspring resulting from such a cross.

b. a cross is made between two horses, both of who are heterozygous black trotter.

- Give a genotype of each parent horse.

- Determine all the possible kinds of gametes each parent can produce





c. Construct a Punnett square and show all the possible gene combinations that results.

d. What is the expected phenotype ration of the offspring?

Explanation:

As given Block color is dominant over chesnut color, so B is dominant over b.

Chestnut color=bb ;

Trotting gait is dominant over  pacing gait, so T is dominant over t .

Pacing gait=tt

Now;  cross between

(a) homozygous black, pacing gait is= BBtt; and horse homozygous for chestnut color, trotting gait is= bbTT

BBtt x bbTT

gametes are ; Bt and bT,

Progeny are BbTt, BbTt,

All progeny will be BbTt  heterozygous Black color and heterozygous trotting gait

b. a cross is made between two horses, both of who are heterozygous black trotter = BbTt X BbTt

 Possible gametes of each parent are;

Parent 1: BT bt Bt bT

Parent 2: BT bt Bt bT

c.  Punnett square and  all the possible gene combinations that results are;

Cross between these gametes

BT bt Bt bT

BT bt Bt bT

possible gene combinations ; BBTT , BbTt , BBTt , BbTT , BbTt , BbTt , BBTt , BbTT , BBTt , Bbtt , BBtt , BbTt , BbTT , bbTt , BbTt , bbTT.

d. expected phenotype ration of the offspring.

Black color and trotting gait  horse 12: chestnut and trotting gait horse 1: Black color pacing gait horse  1: chestnut and trotting gait  horse 2.

so 12:1:1:2

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

i hope this : )