Question

In: Biology

A homozygous groucho fly ( gro, bristles clumped above the eyes) is crossed with a homozygous...

A homozygous groucho fly ( gro, bristles clumped above the eyes) is crossed with a homozygous rough fly (ro, eye abnormality). The F1 females are testcrossed, producing these offspring:

groucho 518

rough 471

groucho, rough 6

wild-type 5

1000

What is the linkage distance between the two genes?
Plot the genes on a map
If the genes were unlinked and the F1 females were mated with the F1 males, what would be the offspring in the F2 generation?

Expert Solution

A homozygous groucho fly ( gro, bristles clumped above the eyes) is crossed with a homozygous rough fly (ro, eye abnormality).

S0, P1- groucho (gro gro ro+ ro+) X rough (ro ro gro+ gro+)

the F1 progenies will be= gro+ gro ro+ ro

A test cross is when F1 progenies is crossed with the individual have a homozygous recessive allele for all genes.

Therefore,

gro+ gro ro+ ro X gro gro ro ro (test cross)

The gametes of the F1 hybrids are - gro+ ro, gro ro+ (parental types) and gro + ro +, gro ro (recombinant types)

gametes of the homozygous recessive plants are - gro ro

With this cross, the number of offsprings are following-

groucho (gro gro ro+ ro) 518 (parental type 1)

rough (gro+ gro ro ro) 471 (parental type 2)

groucho, rough (gro gro ro ro) 6 (recombinant type 1)

wild-type (gro+ gro ro+ ro) 5 (recombinant type 2)

The frequency of the recombinant types is equal to the map distance between two genes

So, (6+5)/1000 = 0.011 = 1.1 %

a. so the distance between two genes is 1.1 cM

b. See the following figures

C. If the genes were unlinked and the F1 females were mated with the F1 males, the offspring in the F2 generation would be

Wild : groucho : rough : groucho, rough = 9:3:3:1

Wild = 562.5

groucho = 187.5

rough = 187.5

grouch, rough = 62.5

(* the number of offspring can not be fractioned. It's only shown for the calculation purpose)

gladiator answered 1 year ago

30) A homozygous groucho fly (g, bristles about the eye) is crossed with a homozygous rough...

30) A homozygous groucho fly (g, bristles about the eye) is crossed with a homozygous rough fly (r, eye abnormality). The F1 females are test crossed to a groucho, rough fly. The following data was obtained. 514 Groucho 466 Rough 11 Groucho, rough 9 Wild type Are these genes linked? Is the F1 in coupling or repulsion phase. Draw out the heterozygous parents genotype on chromosomes. 33) Three corn genes, R, D and Y lie on chromosome 9. The map...

A true breeding red eyed fly with long bristles was crossed to a true breeding white...

A true breeding red eyed fly with long bristles was crossed to a true breeding white eyed fly with stubble bristles. All F1 progeny are red eyed with stubble bristles. An F1 female is crossed to a tester male and the following numbers of progeny are observed: 56 red eyed, stubble bristles; 72 red eyed, long bristles; 61 white eyed stubble bristles; and 68 white eyed, long bristles. You are asked to perform a chi-squared test for this result. 1....

Cinnabar eyes (cn) and reduced bristles (rd) are autosomal recessive characters in Drosophila. A homozygous wild-type...

Cinnabar eyes (cn) and reduced bristles (rd) are autosomal recessive characters in Drosophila. A homozygous wild-type female was crossed to a reduced, cinnabar male, and the F1 males were then crossed to the F1 females to obtain the F2. Of the 400 F2 offspring obtained, 292 were wild type, 9 were cinnabar, 7 were reduced, and 92 were reduced and cinnabar. Briefly explain (2 sentences) these results and estimate the distance between the cn and rd loci.

Female with stubble bristles crossed to a a male with stubble bristles Info: SB-Stubble Bristles +...

Female with stubble bristles crossed to a a male with stubble bristles Info: SB-Stubble Bristles + Wild Type Female 422 SB Male 406 SB Female 192 + Male 187 + 1. Draw the cross and the F1 generation 2. Predict the F1 geneotypes and phenotypic ratios 3. Use goodness of fit/apriori chi squared (X2) analysis to confirm the most likely F1 phenotypic ratio. 4. How is Stubble Bristles inherited ?

In the fruit fly, Drosophila melanogaster, a spineless (sp, no wing bristles) female fly is mated...

In the fruit fly, Drosophila melanogaster, a spineless (sp, no wing bristles) female fly is mated to a male that is claret (cl, dark eyes) and hairless (h, no thoracic bristles). Phenotypically wild type F1 female progeny were mated to fully homozygous (mutant) males and the following progeny (1000 total) were observed. PHENOTYPES NUMBER OBSERVED spineless 316 wild 8 claret, spineless 136 claret 37 claret, hairless 304 hairless, claret, spineless 12 hairless 144 hairless, spineless 43 What is the correct gene map for these genes?...

1)A homozygous tomato plant with red fruit and yellow flowers was crossed with a homozygous tomato...

1)A homozygous tomato plant with red fruit and yellow flowers was crossed with a homozygous tomato plant with golden fruit and white flowers. The F1 all had red fruit and yellow flowers. The F1 were testcrossed by crossing them to homozygous recessive individuals, and the following offspring were obtained: Red fruit and yellow flowers41 Red fruit and white flowers7 Golden fruit and yellow flowers8 Golden fruit and white flowers44 How many map units separate these genes? A)17.6 B)17.1 C)15 D)18.1...

If homozygous green seed-producing plant is crossed to a homozygous yellow seed-producing plant, what percent of...

If homozygous green seed-producing plant is crossed to a homozygous yellow seed-producing plant, what percent of offspring produces yellow seeds? A) 10 B) 50 C) 33 D) 100 E) 25

A Drosophila female homozygous mutant for two recessive genes (a and b) is crossed to a...

A Drosophila female homozygous mutant for two recessive genes (a and b) is crossed to a wild-type male. The F1 are all wild-type. An F1 female is crossed to a double-mutant male and the following phenotypes were seen in the F2: a b 497 + + 460 a + 465 + b 426 Total 1848 Perform a “best fit” or apriori χ2 analysis to determine if genes a and b assort independently. Give the value for χ2, DF and Probability;...

homozygous recessive is crossed with a heterozygote, what percent chance is there of getting a heterozygous...

homozygous recessive is crossed with a heterozygote, what percent chance is there of getting a heterozygous genotype in f1?

in peas puppe flowers are dominant to whote flowers. a homozygous purple flower is crossed to...

in peas puppe flowers are dominant to whote flowers. a homozygous purple flower is crossed to a whitw flower. what proportion of their offspring should be predicted to be white and where does alternative mRNA SPLICING occur?