In chickens, having feathers on legs is dominant to having featherless legs. In a population of 200 chickens, 128 have featherless legs. How many chickens are heterozygous for the "feathered leg" allele? Assume the population is in Hardy-Weinberg equilibrium.

64

Explanation:

Since the population is in Hardy-Weinberg equilibrium and the equilibrium is defined by the equation

p² + 2pq + q²

where the frequency of the homozygous dominant allele F ( feathers on the leg ) = p²,

F of homozygous ( featherless legs) = q²

F of heterogyous ( carrier of featherless allele) = 2pq

F (q²) = 128/200 = 0.64

q = √0.64 = 0.8

and p + q = 1

p = 1 - 0.8 = 0.2

2pq = 2 × 0.2 × 0.8 = 0.32

number of chickens that are heterozgous for the feathered leg allele = 0.32 × 200 = 64

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.