Question

In: Biology

in flour beetles, pygmy (py) is recessive to normal size (py+) and red color (r) is...

in flour beetles, pygmy (py) is recessive to normal size (py+) and red color (r) is recessive to brown (r+). A beetle heterozygous for these characteristics was testcrossed to a red pygmy beetle. The table below shows the numbers and phenotypes from the progeny of this testcross - use this information to answer the following three questions. Progeny phenotype Progeny number

Normal size, brown 180

Normal size, red 20

Pygmy, brown 10

Pygmy, red 190

Total 400 Flag this Question

Question 21. What is the recombination frequency between py and r? Please express your answer as number (no words), in units of centimorgans.

Question 22. If these two genes were completely unlinked, how many progeny (out of 400) would we expect in each phenotypic class in the table above? Express your answer as a number (no words).?

Expert Solution

21) recombination frequency in the percentage of recombinant progenies.

maximum recombination frequency between genes is 50%, if the recombination frequency is 50% then the genes are not linked.

if the genes are linked on a chromosome we expect few recombinant progenies than non-recombinant progenies.

here the number of Normal size, red beetles and Pygmy, brown beetles are less than that of the other two phenotypic classes so Normal size, red beetles and Pygmy, brown beetles are recombinant progenies.

recombination frequency= (number of recombinant progenies/total number of progenies)100

= (( number of Normal size, red + number of Pygmy, brown)/total number of progenies)100

= ( (10+20)/400)100)

= 7.5 %

recombination frequency is the distance between genes in cM

so the answer is 7.5 cM

22) if the genes are unlinked

py+py r+r * pypyrr

	py+r+	py+r	pyr+	pyr
pyr	py+r+/pyr ( normal size brown)	py+r/pyr ( normal size red)	pyr+/pyr ( pygmy, brown)	pyr/pyr( pygmy, red)

if the genes are not linked all the phenotypes are expected in equal proportion.

Normal size, brown: Normal size, red : Pygmy, brown: Pygmy, red = 1:1:1:1

all the phenotypes are expected in equal proportion that is 1/4 each.

Normal size, brown= 4001/4=100

Normal size, red = 4001/4=100

Pygmy, brown = 4001/4=100

Pygmy, red = 4001/4=100

gladiator answered 2 years ago

a. Red green color blindness is a sex linked recessive trait. If a woman with normal...

a. Red green color blindness is a sex linked recessive trait. If a woman with normal vision whose father is colorblind marries a man with colorblindness. What would be the probability that they have a colorblind child? b. Two parents have ABO blood group genotypes. Which of the following blood types could not belong to one of their children? AB, B, O, A. c. A women who is a carrier for colorblindness marries a normal male. What is the probability...

4. In humans, red-green color blindness is recessive to normal sight. The gene for this trait is...

4. In humans, red-green color blindness is recessive to normal sight. The gene for this trait is carried on the X chromosome. In each of the following, give the genotype and phenotype of all possible offspring and their expected ratios. Give the phenotypic ratios of males ♂ and females ♀ separately (ALWAYS FOR X-LINKAGE): (a) a color-blind man married to a normal- sighted woman whose father is color-blind; (b) a man with normal color vision married to a color-blind woman.

In Drosophila the recessive alleles for white eyes is X-linked (normal eye color is red) and...

In Drosophila the recessive alleles for white eyes is X-linked (normal eye color is red) and the recessive allele for vestigial wings is autosomal. A female heterozygous for both of these traits is crossed with a white-eyed vestigial male. What proportion of the FEMALE progeny will be white-eyed with vestigial wings.? (a) 100 % (b) 75 % (c) 50 % (d) 25 % (e) 0 %

1)Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision...

1)Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents? A)XnXn and XnY B)XNXN and XNY C)XNXn and XNY D)XNXN and XnY 2)A poison interferes with the action of RNA polymerase II, but not RNA polymerase I or III. Which of the following is likely to be true of a cell exposed to the poison? A)production of tRNA would be stopped but not...

An X-linked recessive allele, r, produces red-green colorblindness in humans. A normal woman whose father was...

An X-linked recessive allele, r, produces red-green colorblindness in humans. A normal woman whose father was colorblind marries a colorblind man. a. What is the chance that the first child from this marriage will be a colorblind boy? b. What is the chance that the first child from this marriage will be a colorblind girl? c. If the couple have three children, what is the probability that two of them will be colorblind boys and one will be a normal...

A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A...

A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A woman with normal vision whose father is red-green color blind marries a male with normal vision. Which of the following best predicts the phenotypes of their children? A. All of the children will have normal vision. B. All of the daughters will have normal vision, and half of the sons will be red-green color blind. C. All of the daughters will have normal vision,...

Red-green color blindness is due to an X-linked recessive allele in humans. A widow’s peak (a...

Red-green color blindness is due to an X-linked recessive allele in humans. A widow’s peak (a hairline that comes to a peak in the middle of the forehead) is due to an autosomal dominant allele. Consider the following family history: A man with a widow’s peak and normal color vision marries a color-blind woman with a straight hairline. The man’s father had a straight hairline, as did both of the woman’s parents. Use the family history to make predictions about...

14A. Suppose a population of flour beetles has 10,000 individuals. There are two alleles possible for...

14A. Suppose a population of flour beetles has 10,000 individuals. There are two alleles possible for the gene that determines body color: red (B), and black (b). BB and Bb beetles are red, while bb individuals are black. Assume the population is at Hardy–Weinberg equilibrium, with equal frequencies of the two alleles. What would be the expected frequency of red beetles? 14B. What would be the expected frequency of black beetles in the population as described in A? 14C. Assuming...

In human beings, the gene for red green colorblindness (r) is sex linked and recessive to...

In human beings, the gene for red green colorblindness (r) is sex linked and recessive to its allele for normal vision (R), while the gene for freckles (F) is autosomal and dominant over its allele for nonfreckled (f). A nonfreckled, normal visioned woman whose father was freckled and colorblind, marries a freckled, colorblind man whose mother was nonfreckled. a. What is the genotype of the woman's father? b. What is the probability that the couple's first child will be a...

In a certain species of flower, the red allele for flower color (R) is completely dominant...

In a certain species of flower, the red allele for flower color (R) is completely dominant to the pink allele (r). A completely recessive allele (d) at a second gene on a different chromosome allows pigment (color) to be actually deposited within flowers; the lack of pigment results in white flowers. READ CAREFULLY! (a) What is a possible genotype for a pink flower? ___ ___ ___ ___ (b) What is the probability that a flower that is heterozygous for both...