Exam 13: Genes, Chromosomes, and Human Genetics

You are observing a number of human uterine cells with a microscope. In the nucleus of each cell, you can see a mass of condensed heterochromatin at one side of the nucleus. Which chromosome is likely to be included in the condensed heterochromatin?

Which genetic condition has an X-linked recessive inheritance pattern?

Which individual may be a carrier for a recessive X-linked trait in humans?

If two genes are linked on the same chromosome, then ____.

The principles of linkage and recombination were discovered using which organism?

You are working in a research lab on the organism Drosophila melanogaster , and you have been given the job of determining the relative positions of three linked genes for your undergraduate research project. A graduate student in the lab tells you that gene a is 5.0 centimorgans from gene b , and that gene c is 2.7 centimorgans from gene b . What should you do to finish mapping these three genes? What are the likely results that may occur, and how would you interpret such results?

An autosome is a ____.

When two genes on the same chromosome are located 10 map units from each other, ____ of the offspring from a testcross for genetic linkage should have a recombinant phenotype.

In Drosophila melanogaster, the gene for eye color is located on the X chromosome. The allele for red eye color (X^w+) is dominant over the allele for white eye color (X^w). You examine a vial of 100 flies that are all offspring from a single genetic cross. You find both red-eyed females and white-eyed females as well as both red-eyed males and white-eyed males. The genotypes of the parents were ____.

A woman with normal blood clotting mates with a man who has hemophilia. Their first child is a boy who has hemophilia. Tests show that the father and son both have the same form of hemophilia, that it is X-linked, and that the boy has normal genetic inheritance. You can predict that if the couple has more children together, it is likely that ____.

One mechanism of genomic imprinting silences an allele by DNA ____.