chapter 8 homework

Which of the statements describes mosaicism?

- A child with the phenotypic features characteristic of Turner syndrome has a mixture of normal cells and cells with one copy of the X chromosome. - A cancerous tumor develops in a woman's ovary. - A tortoiseshell cat has patches of orange and black fur.

Select the statements that describe the effect of copy number variation on human phenotypes.

- Copy number variations are associated with complex disorders such as autism. - Oncogene overexpression due to a gain in copy number can cause cancer. - Increase in the copy number of immunity genes can result in increased pathogen resistance.

Select the statements that explain why duplication is a driving force for evolution and the generation of new genes.

- Phenotypic variations can occur when random fixed mutations are introduced into a new chromosomal environment. - Genes duplicate and then diverge from the original sequence to create novel genes. - Duplicated genes provide extra copies of DNA that are not constrained by an essential function.

Some people with Turner syndrome are 45,X/46,XY mosaics. How could this mosaicism arise?

A cell loses a Y chromosome soon after fertilization in an XY embryo.

Place the type of translocation and sequence or sequences translocated next to each set of chromosomes. Nonhomologous chromosomes: AB-CDEFG RS-TUVWX

Translocation 1: AB-CD RS-TUVWXEFG nonreciprocal location of EFG Translocation 2: AUVB-CDEFG RS-TWX nonreciprocal translocation of UV Translocation 3: AB-TUVFG RS-CDEWX reciprocal translocation of CDE and TUV Translocation 4: AB-CWG RS-TUVDEFX reciprocal translocation of DEF and W

Familial Down syndrome is similar to primary Down syndrome in that it is caused by trisomy 21. However, in familial Down syndrome, all or part of the third copy of chromosome 21 has translocated onto another autosome, typically chromosome 14. In cases of familial Down syndrome, one of the parents of the affected child is often a carrier of a translocated chromosome. The translocation carrier parent does not have Down syndrome because he or she has a total of two copies of chromosome 21. Suppose that a woman is a translocation carrier of chromosome 21 on chromosome 14. She conceives six zygotes with a normal man who carries no aneuploidies. Match the description of the chromosomes inherited by each zygote with the viability of the zygote.

Viable normal, or translocation carrier: -two normal copies of 14, two normal copies of 21 -one normal copy of 14, one normal copy of 21, one 21 to 14 translocation Viable, with Down syndrome: -one 21 to 14 translocation, two normal copies of 21, one normal copy of 14 Inviable: -one normal copy of 14, two normal copies of 21 -two normal copies of 14, one normal copy of 21 -one 21 to 14 translocation, one normal copy of 21, two normal copies of 14

Select the definition of euploidy.

a complete chromosome set or an exact multiple of the haploid chromosome set

Which term describes the rearranging of genetic material between nonhomologous chromosomes without a net loss or gain of genetic material?

translocation

The image portrays a representation of a human karyotype What type of genetic disorder is shown in this karyotype?

trisomy

Use the karyotype interactive to answer the question. Aneuploidy is an umbrella term referring to multiple kinds of conditions in which an individual has an abnormal number of chromosomes for their species. Some of the patients on the abnormal tab of the karyotype virtual interactive suffer from different types of aneuploidy. Use the interactive to determine from which form of aneuploidy patient 251 suffers.

trisomy