Bar eye (B) is a dominant and sex-linked trait of Drosophila. Curved wings (cu) and black...

Bar eye (B) is a dominant and sex-linked trait of Drosophila. Curved wings (cu) and black body (bl) are recessive traits, both found on chromosome 2, separated by 24 map units. A homozygous Bar-eyed, black-bodied female is crossed to a true-breeding male expressing curved wings. The heterozygous F1 female is then crossed to a male expressing all three traits. At what frequency among the F2 would you expect to find a completely wild type male?

How often would you find a Bar eyed, curved wing female?

Expert Solution

Cross 1: (Black bodied, Bar eyed female crossed to Male with Curved wings)
bl c+/bl c+; X^B/X^Bx bl+ c/bl+ c; X/Y

F1 --> bl c+/bl+ c ; X^B/X (F1 Heterozygous Female)

Cross 2 (F1 Heterozygous female crossed to male expressing all three traits):

bl c+/bl+ c ; X^B/X x bl c/bl c ; X^B/Y

The female parent of Cross 2 produces the following gametes:

Gametes and the proportion of gametes
Gamete	Gamete Type	Proportion	Rationale
bl c+; X^B	Parental	19%	Since the two loci are 24 map units apart, recombination would occur in 24% of all meioses. Therefore, 76% of all gametes would be parental, with each class of parental gametes represented equally
bl c+; X	Parental	19%
bl+ c ; X^B	Parental	19%
bl+ c ; X	Parental	19%
bl+ c+; X^B	Recombinant	6%	24% of all meioses would be recombinant, and all recombinant gametes would be represented equally.
bl+ c+; X	Recombinant	6%
bl c ; X^B	Recombinant	6%
bl c ; X	Recombinant	6%

Now, the tester male (Male used in Cross 2) would produce half gametes with the X chromosome and half with the Y chromosome.

Therefore, the progeny proportions are:

A completely normal male is 3% of the F2 progeny.

A Bar-eyed, Curved Wing Female would occur in 19% of female progeny.

gladiator answered 8 months ago

In Drosophila black body (B) is dominant to gray (b) and long wings (L) is dominant...

In Drosophila black body (B) is dominant to gray (b) and long wings (L) is dominant to short wings (l). The F1 flies were produced by crossing a homozygous black, homozygous long winged fly with a gray short winged fly. (4) a) Give the genotypes of the Parents and the F1. b) If an F1 is testcrossed, what is the expected phenotypic ratio? c) If the F1 are allowed to interbreed what are the expected phenotypes and probably proportions in...

Colorblindness is a sex linked trait in humans. Normal vision is a sex linked dominant trait....

Colorblindness is a sex linked trait in humans. Normal vision is a sex linked dominant trait. A man’s maternal grandmother had normal vision; his maternal grandfather was colorblind; his mother is colorblind; his father has normal vision. What are the genotypes of the two grandparents and parents mentioned? What type of vision does the man have himself? What type have his sisters? If he should marry a woman genotypically like one of his sisters (he is not marrying one of...

In flies, eye color is a sex-linked trait. At this locus, the wild-type allele results in...

In flies, eye color is a sex-linked trait. At this locus, the wild-type allele results in red eye color and the mutant results in white eye color. Start with the P generation in which one parent has red eyes and the second parent has white eyes, and discuss offspring and crosses in the F1 and F2 generations in the following two conditions: 1. male with white eyes and female with red eyes; 2. male with red eyes and female with...

In Drosophila, the recessive dp allele of the dumpy gene produces short, curved wings, while the...

In Drosophila, the recessive dp allele of the dumpy gene produces short, curved wings, while the recessive allele bw of the brown gene causes brown eyes. In a testcross using females heterozygous for both of these genes, the following results were obtained: wild-type wings, wild-type eyes 178 wild-type wings, brown eyes 185 dumpy wings, wild-type eyes 172 dumpy wings, brown eyes 181 In a testcross using males heterozygous for both of these genes, a different set of results was obtained:...

1.In fruit flies, eye color is an X-linked trait. Red eyes (XR) are dominant over white...

1.In fruit flies, eye color is an X-linked trait. Red eyes (XR) are dominant over white eyes (Xr)A homozygous dominant female mates with a white-eyed male. What is the phenotypic ratio among males? a.1:0 (all male offspring will have red eyes) b.1:1 (half of the male offspring will have red eyes and half will have white eyes) c.0:1 (all male offspring will have white eyes) 2.In fruit flies, eye color is an X-linked trait. Red eyes (XR) are dominant over...

In Drosophila, red eyes (E) are dominant over white (e) and normal wings (W) are dominant...

In Drosophila, red eyes (E) are dominant over white (e) and normal wings (W) are dominant over shriveled wings (w). Use the addition and multiplication rules to calculate the phenotypic ratios of the cross of Eeww and EeWw. 1. Cross of Ee x Ee: 2. Cross of ww x Ww: 3. Red eyes and normal wings: 4. Red eyes and shriveled wings: 5. White eyes and normal wings: 6. White eyes and shriveled wings:

Miniature wings in Drosophila are due to an X-linked allele (Xm) that is recessive to the...

Miniature wings in Drosophila are due to an X-linked allele (Xm) that is recessive to the wild-type allele for normal long wings (X+). Sepia eyes are produced by an autosomal allele (se), which is recessive to the wild-type allele for red eyes (se+). A female that is homozygous for normal wings and has sepia eyes is crossed with a male that has miniature wings and is homozygous for red eyes. The F1 offspring are intercrossed to produce the F2 generation....

Black body (b) and purple eye (pr) are recessive autosomal mutations in Drosophila. Bridges crossed b/b...

Black body (b) and purple eye (pr) are recessive autosomal mutations in Drosophila. Bridges crossed b/b females and pr/pr males. F2 cross produced 684 wild-type, 371 black-bodied, and 300 purple-eyes flies. Do these result indicate that the b and pr genes are closely linked? Explain. Remember that there is no crossing over in male Drosophila

Bar is a dominant mutation on the Drosophila X-chromosome. A Bar male crossed to a wildtype...

Bar is a dominant mutation on the Drosophila X-chromosome. A Bar male crossed to a wildtype female giving the following results: Bar females 998 wild type males 1021 wild type female 1 Remember: in Drosophila two X-chromosomes make a female fly and one X-chromosome makes a male; the Y is irrelevant. XXX is lethal. Part I: What are the complete and exact genotypes of each parent and each type of offspring? female parent: male parent:...

In fruit flies, a grey body is dominant to a black body, and normal wings are...

In fruit flies, a grey body is dominant to a black body, and normal wings are dominant to vestigial wings. Flies are heterozygous for both grey bodies and normal wings were crossed with flies that had black bodies and vestigial wings. The following results were obtained: Phenotype Number of flies Grey body/Normal wings 482 Black body/Vestigial wings 472 Grey body/Vestigial wings 103 Black body/Normal wings 92 The results indicate that the genes for wings and body color are on the...

Question