6. You have identified an autosomal gene that contributesto tail size in male guppies, with a dominant allele B forlarge tails and a recessive allele b for small tails. Femaleguppies of all genotypes have similar tail sizes. Youknow that female guppies usually mate with males withthe largest tails, but the effects of population densityand the ratio of the sexes on this preference have notbeen studied. You therefore place an equal number ofmales in three tanks. In tank 1, the number of femalesis twice the number of males. In tank 2, the numbers ofmales and females are equal. In tank 3, half as manyfemales as males are present. After mating, you findthe following proportions of small-tailed males amongthe progeny: tank 1, 16%; tank 2, 25%; tank 3, 30%.a. In your original population (before the animals wereplaced in the three tanks), 25% of the males havesmall tails. Assuming that the allele frequencies inmales and females are the same, calculate the frequencies of B and b in your original population.b. Calculate Δq for each tank.c. If WBB = 1.0, what is WBb for each tank?d. If WBB = 1.0, is Wbb less than, equal to, or greaterthan 1.0 for each tank?
Genetic Variation
Genetic variation refers to the variation in the genome sequences between individual organisms of a species. Individual differences or population differences can both be referred to as genetic variations. It is primarily caused by mutation, but other factors such as genetic drift and sexual reproduction also play a major role.
Quantitative Genetics
Quantitative genetics is the part of genetics that deals with the continuous trait, where the expression of various genes influences the phenotypes. Thus genes are expressed together to produce a trait with continuous variability. This is unlike the classical traits or qualitative traits, where each trait is controlled by the expression of a single or very few genes to produce a discontinuous variation.
6. You have identified an autosomal gene that contributes
to tail size in male guppies, with a dominant allele B for
large tails and a recessive allele b for small tails. Female
guppies of all genotypes have similar tail sizes. You
know that female guppies usually mate with males with
the largest tails, but the effects of population density
and the ratio of the sexes on this preference have not
been studied. You therefore place an equal number of
males in three tanks. In tank 1, the number of females
is twice the number of males. In tank 2, the numbers of
males and females are equal. In tank 3, half as many
females as males are present. After mating, you find
the following proportions of small-tailed males among
the progeny: tank 1, 16%; tank 2, 25%; tank 3, 30%.
a. In your original population (before the animals were
placed in the three tanks), 25% of the males have
small tails. Assuming that the allele frequencies in
males and females are the same, calculate the frequencies of B and b in your original population.
b. Calculate Δq for each tank.
c. If WBB = 1.0, what is WBb for each tank?
d. If WBB = 1.0, is Wbb less than, equal to, or greater
than 1.0 for each tank?
Trending now
This is a popular solution!
Step by step
Solved in 2 steps
