Question

In: Biology

The allele b gives Drosophila flies a black body, and b+ gives brown, the wild-type phenotype....

  1. The allele b gives Drosophila flies a black body, and b+ gives brown, the wild-type phenotype. The allele wx of a separate gene gives waxy wings, and wx+ gives nonwaxy, the wild-type phenotype. The allele cn of a third gene gives cinnabar eyes, and cn+ gives red, the wild-type phenotype. A female heterozygous for these three genes is testcrossed, and 2,424 progeny (you could also use n=2,423) are classified as follows:

    cn+ · wx+ · b 101
    cn · wx+ · b+ 768
    cn · wx+ · b 20
    cn+ · wx+ · b+ 323
    cn+ · wx · b 848
    cn · wx · b+ 101
    cn · wx · b 242
    cn+ · wx · b+ 20


    Calculate the recombinant frequencies for  b-wx,  b-cn, and  wx-cn.

    Which gene is in the middle: b, wx, or cn?

    Screen shot of table in case of formatting issues:

    NOTE: the genotypes in the table below were released on Friday July 10, but there are errors which have been corrected above.

    cn+ · wx · b 101
    cn · wx+ · b+ 768
    cn · wx · +b 20
    cn+ · wx+ · b+ 323
    cn+ · wx · b 848
    cn · wx · b 101
    cn · wx+ · b 242
    cn+ · wx · b 20

Solutions

Expert Solution

Answer-

A) gene b is in the middle.

B) recombinant frequency between b-wx = 9.99% ; cn-b = 24.97% ; cn-wx = 33.3%

The calculation is given below:


Related Solutions

A student crosses a phenotypically wild type Drosophila female to a male with unknown phenotype (that...
A student crosses a phenotypically wild type Drosophila female to a male with unknown phenotype (that unreliable lab partner confused the fly stocks again!). There are two genes segregating in the cross. The “vg” phenotype has small wings and the “cn” phenotype has light eye color, and both genes are on an autosome. Remember that Drosophila males do not exhibit meiotic recombination. (hint: you may need a page of blank paper to work possible crosses before you answer the questions....
In dogs, the allele for black coat color (B) is dominant to the allele for brown...
In dogs, the allele for black coat color (B) is dominant to the allele for brown coat color (b). But if a dog has two copies of the recessive allele for a pigment-depositing gene (e), it can only have yellow coat color. In a cross of two doubly heterozygous black dogs (BbEe x BbEe), what fraction of the next generation would we expect to be yellow? WHY? a.1/8 b.1/4 c.2/3 d.3/16
In rabbits, black hair depends on a dominant allele, B. and brown on a recessive allele,...
In rabbits, black hair depends on a dominant allele, B. and brown on a recessive allele, b. Short hair is due to a dominant allele, S, and long hair to a recessive allele, s. A short, black haired male rabbit who is homozygous dominant for both traits is mated with a brown, long haired female a. Write the genotype (in letters) of both parents. b. Draw the Punnett square below illustrating the cross of the parental rabbits. c. What percentage...
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 fruit flies, bristle shape is controlled by an X-linked gene. The dominant wild-type allele (+)...
In fruit flies, bristle shape is controlled by an X-linked gene. The dominant wild-type allele (+) results in normal bristles, while the recessive allele (sn) results in short 'singed' bristles. A normal-bristled female offspring of a male with singed bristles is crossed with a normal-bristled male. If we consider only the progeny that have normal bristles, what is the ratio of females : males among these? 2:3 1:3 3:1 1:1 2:1 3:2 1:2
In Drosophila , a recessive autosomal allele, ebony (e) produces a black body colour when homozygous....
In Drosophila , a recessive autosomal allele, ebony (e) produces a black body colour when homozygous. Another recessive autosomal allele, black (b) also produces a black body colour when homozygous. Wild type flies are grey.  Flies with genotypes e/e b+/-, e+/- b/b, and e/e  b/b  show identical colour phenotype. If e/e  b+/b+ ebony flies are crossed with e+/e+ b/b black flies  than; c) What phenotypic ratios would be observed from the crosses F1 x true-breeding ebony, and F1 x true-breeding black? d) What would be...
In Drosophila melanogaster, black body (b) is recessive to gray body (b+), purple eyes (pr) are...
In Drosophila melanogaster, black body (b) is recessive to gray body (b+), purple eyes (pr) are recessive to red eyes (pr+), and vestigial wings (vg) are recessive to normal wings (vg+). These three genes are linked with pr located between b and vg at a genetic distance of 6 cM from b and 13 cM from vg. Previous experiments have shown that the interference associated with these three genes is 0.5. A fly with a black body, purple eyes and...
Purebred lines of fruit flies with wild type (tan) body color and stubby bristles are mated...
Purebred lines of fruit flies with wild type (tan) body color and stubby bristles are mated to flies with ebony bodies and normal bristles. The resulting F1 offspring all have a normal wild-type body color and stubby bristles. The F1 flies are crossed with flies recessive for both traits (i.e. ebony bodies and normal bristles). a. What phenotypes and ratios of phenotypes would you expect to find among the offspring produced by crossing the F1 with flies recessive for both...
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...
A protein with a wild-type allele (Pwt) and protein with a mutant allele (Pm) are one...
A protein with a wild-type allele (Pwt) and protein with a mutant allele (Pm) are one amino acid in the position 12 of the protein chain. The mutant allele's sequence is 5'CTT whereras the wild-type allele's sequence is 5'CAT. Using an amino acid chart, find : Pwt in position #12 Pm in position #12
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT