Exam 6: Genetic Linkage and Mapping in Eukaryotes

While mapping two genes in Drosophila, you observe 30 recombinants among 200 total offspring. What is the distance between these genes?

Assume that genes C and D are located on the same chromosome. On one chromosome, alleles C and D are found, while the homologue contains alleles c and d. Which of the following would be evidence of a recombination event?

Creighton and McClintock worked with ________ and their model system to show that homologous chromosomes physically exchange genetic information during crossing over.

The visual proof that chromosomes exchange pieces of information during crossing over was provided by ________.

A negative interference value indicates that the first crossover event enhanced the occurrence of additional crossover events in the region.

The genotype hsp+ HSP- is something that you could easily expect to find in the fungus Neurospora crassa.

The rearrangement of alleles by the process of crossing over is called genetic linkage.

Two genes that are located on the same chromosome are said to be ________.

A map unit or centimorgan is equal to a 10% recombination frequency.

You notice that in most biology and genetics textbooks, the authors show that Gregor Mendel used flower color as one of his pairs of traits. The purple flower phenotype is dominant to the white flower phenotype. However, if you go back to Mendel's experiments, you see that he actually studied seed coat color. The purple seed coat phenotype was dominant to the white seed coat phenotype. Mendel did note that plants with purple seed coats had purple flowers and plants with white seed coats had white flowers. Is the gene for seed coat color pleiotropic because it also affects flower color, or are the seed coat color gene and the flower color gene very closely linked? To find out the answer to this question, you assume that the genes for flower color and seed coat color are different genes, and your null hypothesis is that they assort independently. You designate the flower color gene wf and the seed coat color gene sw. Plants that are WF__, SW___ have purple flowers and purple seed coats. Plants that are wf wf, ws ws have white flowers and white seed coats. You do the testcross WF wf, SW sw X wf wf, sw sw and collect 15,206 offspring. What result would tell you that the wf and sw loci are probably the same, pleiotropic locus?

Map distances above 50 are considered unreliable due to the occurrence of double-crossovers between the genes.

In fungal gene mapping, the abbreviation NPD stands for new parental ditype.

Crossing over is more likely to occur between genes that are ________ on a chromosome.

A fungal reproductive structure that contains all of the products of a single meiotic division is called the ascus.

An organism that contains patches of tissue that vary for a specific characteristic such as a pigment, can be an example of which of the following?

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

Which of the following are highly desirable characteristics of an organism that make it relatively easy to construct a genetic linkage map?

Twin spotting provides evidence of what genetic event?

A genetic linkage map indicates that precise distance between two genes of interest.

Which of the following statistical tests is used to determine if two genes are linked or assorting independently?