Question

In corn, there are three recessive genes (a, b, and r) that are linked on chromosome...

In corn, there are three recessive genes (a, b, and r) that are linked on chromosome 3. A homozygous recessive plant is crossed with a wild-type plant. The F1 is crossed to get an F2 generation with 1370 individuals that had the following genotypes:

a b r : 44

aBr: 460

A b r : 14

abR: 164

AbR: 474

aBR: 16

ABr: 158

ABR: 4

It is possible to develop a gene map, showing the order of the loci and the distance between them by observing the number of offspring showing recombinant phenotypes.

1.What is the order of the three genes on chromosome 3?

2. What is the correct equation for calculating map distance? (Note SCO = Single Cross Over, DCO = Double Cross Over)

3.What is the map distance between the B and R genes?

4. What is the map distance between the R and A genes?

Science   Biology   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

The greater number are of parental type and the lowest number are of double cross over type.

The middle gene is swapped during the double cross over.

Please look in the image for solution:

Please rate high...

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
In mice, three recessive genes (rg, mg, and at) are linked on chromosome 3. A homozygous...
In mice, three recessive genes (rg, mg, and at) are linked on chromosome 3. A homozygous mouse for the recessive genes is crossed with a wild-type mouse. The F1 is testcrossed to get an F2 generation with the following results: at rg +           1                      at   +   +         15 + rg +           69                    at rg mg         36 + + mg          1                      + rg mg         9 at + mg         76                    +   +   +         16 What is the gene...
A given chromosome contains three linked genes, B, T, and R that encode for the phenotypes:...
A given chromosome contains three linked genes, B, T, and R that encode for the phenotypes:             B = Black, b = white             T = Tall, t = short             R = Round, r = square To determine if the genes are linked a standard three-point testcross was done and the resulting offspring had the following phenotypes. Answer the based on this information.                                                                                                                                    Alleles 52        Black, tall, round                                                                                 BTR 315      Black, short, square (Highest) Btr 75        Black, tall,...
In corn, the trait for yellow seedlings (g) is recessive to green seedlings (G), and waxy...
In corn, the trait for yellow seedlings (g) is recessive to green seedlings (G), and waxy endosperm (w) is recessive to starchy endosperm (W). The two genes assort independently. A cross between a homozygous green, waxy plant and a homozygous yellow starchy plant produced F1 progeny that were all phenotypically green, starchy. a) If F1 individuals are interbred (self-pollinated), what phenotypes and in what proportions (ratios) would you expect in the F2 generation progeny b) List the expected F2 genotypes...
The genes a, b, and c, are linked on chromosome 3 in Drosophila melanogaster. You testcross...
The genes a, b, and c, are linked on chromosome 3 in Drosophila melanogaster. You testcross a triply heterozygous female fly (she looks wild type) and obtain the following phenotypes among the progeny: abc 23 +++ 22 a++ 49 +bc 46 ab+ 420 ++c 435 a+c 3 +b+ 2 1000 A) Draw the combination of the wild-type and/or mutant alleles on each homolog of chromosome 3 for the triply heterozygous mother fly. (the order of alleles is not important for...
Maize breeders is trying to determine the gene order on a metacentric chromosome. They testcross a...
Maize breeders is trying to determine the gene order on a metacentric chromosome. They testcross a maize plant heterozygous for three linked genes with the following recessive alleles (a,b, and d), the following phenotypes and numbers of progeny were obtained (see to right). Assume a dominant recessive relationship between the alleles for each gene (+ is wildtype phenotype). ++d - 460 ab+ - 476 +bd - 19 a++ - 20 a+d - 12 +b+ - 12 A) (2 points) Which...
Three Drosophila genes on the X chromosome occupy three different loci. The mutant versions of these...
Three Drosophila genes on the X chromosome occupy three different loci. The mutant versions of these genes are y for yellow body ct for cut wing ec for echinus (spiky eyes) When a cross is between female X, and male Y flies, the P and F1 have the following genotype + + +/y ct ec When the F1 is selfed to create the F2, most wild type genes remain linked on the same chromosome, as do the mutant genes on...
Consider the genes A and B that are located on mouse chromosome 5. They are 30...
Consider the genes A and B that are located on mouse chromosome 5. They are 30 centimorgans (i.e. map units) apart. If the cross A b/a B x a b /a b were made, at what frequency would you expect individuals homozygous recessive for both genes to occur in the progeny of this cross? In mice, recombination occurs in both sexes. Choose the best answer.
1. The genes B, Q and R are located on a chromosome as shown below: B...
1. The genes B, Q and R are located on a chromosome as shown below: B 40 cM Q 30 cM R B, Q and R are completely dominant to b, q and r. In the cross, B r X b r b R b r What is probability of obtaining offspring which are homozygous recessive for b and r? A. 0.35 B. 0.70 C. 0 D. 0.25 E. 0.50
In Drosophila, black, purple, and curved are three recessive genes. A trihybrid female is testcrossed and...
In Drosophila, black, purple, and curved are three recessive genes. A trihybrid female is testcrossed and the following offspring are obtained: (10 points) Black, purple, curved 5617 Wild-type 5701 Curved, purple 388 Black 367 Curved 1412 Black, purple 1383 Purple 60 Black, curved 72 a) What are the parental genotypes? b) Which are the double cross-overs? c) Calculate the map distance between each gene. (Thank you in advance)
In guinea pigs, rough coat (R) is dominant over smooth coat (r) and black (B) is...
In guinea pigs, rough coat (R) is dominant over smooth coat (r) and black (B) is dominant over white (b). R and B are independent genes. Cross a homozygous rough black animal with a smooth white one. What are the genotypes and phenotypes of the offspring? Choose any two offspring and cross them, determining the genotypes and phenotypes of the next generation.
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT