Purchase Solution

Recombinant classes, genotypes and linkage arrangements

Not what you're looking for?

Ask Custom Question

I need help with the following problem set. Please give a detailed set of answers to better assist me with understanding the genetic concepts.

Dihybrid test crosses are made between each pairwise combination of the three genes C, D, and E with the following results:

CD: 222 CE: 48 DE: 198
Cd: 280 Ce: 455 De: 289
cD: 280 cE: 445 dE: 311
cd: 218 ce: 52 de: 202
___________________________
1000 1000 1000 total

15. Which are the recombinant classes in these three crosses?

16. Give the genotypes of the dihybrids in these three crosses, showing linkage arrangements.

17. Draw the map for these three genes, indicating the order and the lengths of the intervals in map units.

18. What can you say about crossover interference based on this data set?

19. Why do the map distances not add up?

Purchase this Solution
Solution Preview

Please see the attached file.

A test cross involves crossing a heterogygous genotype with a homozygous one. Dihybrid refers to the fact that we are looking at a test cross for two genes at a time. For another example see http://www.saburchill.com/IBbiology/chapters03/008.html

The given crosses include:
CcDdxccdd
CcEexccee
DdEexddee

To yield:
CD: 222 CE: 48 DE: 198
Cd: 280 Ce: 455 De: 289
cD: 280 cE: 445 dE: 311
cd: 218 ce: 52 de: 202
___________________________
1000 1000 1000 total

In the first cross of CcDdxccdd we would expect:

CD cD Cd cd
cd CcDd ccDd Ccdd ccdd
cd CcDd ccDd Ccdd ccdd
cd CcDd ccDd Ccdd ccdd
cd CcDd ccDd Ccdd ccdd

There should be an even ratio of the four genotypes and in our test cross there ...

Purchase this Solution
Free BrainMass Quizzes
Cellular Respiration

This quiz is a review for cellular respiration.

Basic Immunology Quiz

Intro to immuno quiz. Covers the basics of immunology and recognition of foreign substances by the body.

Basic Concepts in Neuroscience

This quiz provides a review of the basic concepts in neuroscience.

Nerves and the Nervous System

This quiz will assess your knowledge of the nervous system and how nerves send signals around the body.

The Transfer of Energy in an Ecosystem

This quiz will assess your knowledge of how energy is transferred in an ecosystem and the different levels of trophic organization.

View More Free Quizzes
Related BrainMass Solutions

  • Linkage mapping example problem

    One linkage map unit (LMU) is 1% recombination. Thus, the linkage map distance between two genes is the percentage recombination between those genes. In this case, we have a total of 10 (5+5) recombinant offspring, out of 40 total offspring.

  • Genotypes and Linkages for Drosophilas

    Hairy, white 2 Yellow, white 360 Hairy, yellow, white110 Give genotypes of the parents and F1 and note any linkage relations and map distances.

  • Punnett Squares and Pedigrees

    c) Use symbols to describe the genotypes of all five sets of parents. d) Do you see evidence of linkage? Quantitative if possible. (Careful, not every family may be informative here)...

  • order of the loci in the chromosome

    of alleles on each the mothers chromosomes Answer: abD ABd 2) which is the sons are recombination, bw what genes is the cross over answer: abD is result of combination crossing over between B and D 3) list other possible recombinant genotypes

  • Understanding chromosome mapping techniques.

    p=30-50% Therefore this data is a common deviation from a 1:1:1:1 ratio, and there is no need to postulate linkage. The chromosome mapping techniques are examined.

  • Determine mapping distance

    The two most common genotypes are AaBb and aabb, which are the parental genotypes.

  • Drosophilla crosses

    In a lab strain of Drosophila, cinnabar (cn) and brown (bw) are recessive eye colour mutations known to be 41 m.u. apart on chromosome 2. When similar mutant alleles were induced in a strain from nature, the same linkage of cn and bw was observed.

  • Determine the linear sequence of these three genes

    In order to calculate the map distance between the genes and their order we need to sort out the parental genotypes form the recombinant ones (the ones that result from crossing over).

  • Case Management and Effective Linkage

    360378 Case Management and Effective Linkage What is one possible barrier to an effective linkage?

View More Related Solutions