Exam 11: Genes, Chromosomes, and Human Genetics

Which of the following occurs in cells of human individuals with three or more X chromosomes? a.Two X chromosomes remain active, and all others are inactivated. b.One X chromosome remains active, and the rest are inactivated. c.All of the X chromosomes remain active. d.Two X chromosomes remain active in females and one remains active in males; the rest are inactivated.

Which of the following best describes sex-linked genes?

-Which genetic condition is revealed in the karyotype display?

Suppose that you examine a vial of 100 flies that are all offspring from a single genetic cross. Also suppose that you find both red-eyed females and white-eyed females, as well as both red-eyed males and white-eyed males. The allele for red eye colour (X^w+) is dominant over the allele for white eye colour (X^w). Which of the following describes the genotypes of the parents?

Suppose that crossing-over during meiosis occurs within a region where one of the homologous chromosomes has an inversion with respect to the other homolog. Which chromosomal alterations would you expect to find in the gametes produced by this organism? a.balanced translocations b.translocations c.both duplications and deletions d.deletions

Which of the following is the molecular mechanism responsible for genomic imprinting?

Suppose that a woman with normal blood clotting mates with a man who also has normal blood clotting, and that their first child is a boy who has X-linked hemophilia. Which statement best predicts the outcomes of their mating?

Which term refers to an individual with three or more copies of each of their chromosomes?

Which of the following is most likely to happen to a human polyploid?

How are mitochondria inherited in most multicellular organisms?

Which of the following disorders has X-linked recessive inheritance?

Which autosomal dominant genetic trait associated with a gene on human chromosome 4 leads to a type of dwarfing due to defective cartilage formation?

Suppose that in Drosophila melanogaster, the allele for red eyes is dominant over the allele for purple eyes, and the allele for a grey body is dominant over the allele for a black body. Also suppose that a testcross was done to check for genetic linkage between the genes for these traits, with the following results for the offspring: 478 flies with red eyes and a black body 27 flies with red eyes and a grey body 462 flies with purple eyes and a grey body 33 flies with purple eyes and a black body Which of the following best represents the map distance between the genes for these two traits?

How is the distinctive fur pattern of a calico cat produced?

Which process is generally the cause for the production of recombinant offspring for two genes on the same chromosome?

Suppose you are a genetic counsellor, and a man and woman come to you with concerns that if they have a child together, it could have hemophilia. Also suppose that the man has an X-linked recessive form of hemophilia, but the woman does NOT, and that genetic tests reveal the woman is NOT a carrier for hemophilia. Which of the following is the best advice you could give them?

In humans, which condition does sex determination generally depend upon?

Suppose that a woman with normal blood clotting mates with a man who has X-linked hemophilia. Given that the woman is heterozygous for the trait, which statement best predicts the outcomes of their mating?

Which sex chromosome combinations would you expect to find in a male calico cat?

Suppose an individual is born with both an X and a Y chromosome, but the Y chromosome has a mutation that eliminates the function of the SRY gene. How would this person appear phenotypically?