Exam 5: Linkage, Recombination, and the Mapping of Genes on Chromosomes

If the p value corresponding to a given $\chi$ ² value and number of degrees of freedom exceeds 0.05, then the null hypothesis is rejected and it is predicted that the two genes being evaluated are not linked.

What is the genotype of the females that gave rise to these progeny?

In Drosophila, the genes b, c, and sp are linked and arranged as shown below: b--30 mu--c--20 mu--sp This region exhibits 90% interference.How many double crossovers would be recovered in a three-point cross involving b, c, and sp out of 1000 progeny?

In tetrad analysis, the criterion for linkage of two genes is

The pairwise map distances for four linked genes are as follows: A-B = 22 m.u., B-C = 7 m.u., C-D = 9 m.u., B-D = 2 m.u., A-D = 20 m.u., A-C = 29 m.u.What is the order of these four genes?

Which of the following linkage maps correctly shows the order and distance between the px, sp, and cn genes?

his4/TRP1; his4/TRP1; HIS4/trp1; HIS4/trp1

What happens physically during the process of crossing over?

Large sectors suggest a mitotic recombination event late in the growth of a yeast colony.

Another name for a chromosome is a _______, since it contains genes that are often inherited together.

A linkage group can be defined as genes that may be so far apart on a chromosome that they cannot be shown to be linked directly but they can be shown to be on the same chromosome due to their linkage with other genes.

Recombination frequencies near 50% suggest that

ws⁺; ws⁺; ws; ws; ws⁺; ws⁺; ws; ws

Which of the three genes is in the middle?

What is the genotype of the mother of these progeny?

In Drosophila, the genes y (yellow body) and car (carnation eyes) are located at opposite ends of the X chromosome.In doubly heterozygous females (y⁺ car⁺ / y car), a single chiasma is observed somewhere along the X chromosome in 90% of the examined oocytes.No X chromosomes with multiple chiasmata are observed.What percentage of the male progeny from such a female would be recombinant for y and car?

Which of the following types of tetrads contain two recombinant and two parental asci?

HIS4/trp1; HIS4/TRP1; his4/TRP1; his4/trp1

Mitotic recombination occurs between homologous chromosomes.In which of the following would you not expect to encounter mitotic recombination?

Assume a double crossover occurs in this pair of chromosomes that results in chromatids of the genotype AbC and aBc.If the first crossover (the one between A and B) involves chromatids 1 & 4, which chromatids could be involved in the second crossover?