BIOL 117 Chapter Notes - Chapter 15: Gamete, Chromosome, Aneuploidy

43 views5 pages

maroonhare625

11 Jan 2019

School

Department

Course

Professor

For unlimited access to Textbook Notes, a Class+ subscription is required.

Document Summary

According to this theory, mendelian genes have specific loci (positions) on chromosomes, and it is the chromosomes that undergo segregation and independent assortment. The two alleles for each gene separate during gamete formation. Alleles of genes on nonhomologous chromosomes assort independently during gamete formation. Wild type the phenotype for a character most commonly observed in populations. Sex-linked gene a gene located on either sex chromosome. Duchenne muscular dystrophy a sex-linked disorder characterized by a progressive weakening of the muscles and loss of coordination. Hemophilia a sex-linked recessive disorder defined by the absence of one or more of the proteins required for blood clotting. Barr body the inactive x in each cell of a female condenses into a compact object, lies along the inside of the nuclear envelope. Linked genes genes located on the same chromosome that tend to be inherited together in genetic crosses.

Related Questions

Which of the following statements is accurate (select all that apply)

A	Haploid individuals can be heterozygous.
B	Two homologous chromosomes have identical copies of the same genes.
C	Mendel's law of segregation refers the separation of homologous chromosomes during meiosis.
D	During independent assortment, sister chromatids separate from each other.
E	Phenotype refers to the genetics make up of an individual.

fuchsiaswan22

Which of these statements is incorrect?

Syntenic genes are located on the same chromosome.

Independent assortment results in recombinant chromosomes.

You can reliably predict the relative genetic distance fromgenesâ physical distance on a chromosome.

Linked genes are always syntenic.

What is the relative genetic distance between two linked genesif the recombination frequency is 0.49?

0.49 cM

4.9 cM

49 cM

490 cM

What statement best explains the distortion in Mendelian ratiosobserved by Bateson & Punnett in 1905? (Reminder: they found anoverrepresentation of F2 offspring showing both dominant orrecessive phenotypes, and an underrepresentation of offspringdisplaying one dominant and one recessive phenotype)

Human error: they should have been more careful about theirexperimental setup.

Gene linkage: Genes for flower color and pollen shape arephysically close on the same chromosome, leading to a breakdown inthe independent assortment of the alleles for these traits.

Chromosome crossover: Homologous recombination of twochromatids during meiosis caused the alleles to shuffle, resultingin a breakdown of the independent assortment of the alleles forthose genes.

Random variation: No two situations are alike. In finitepopulations, you are going to get some variation across a mean.

When determining the relative genetic distance between twogenes, why is dihybrid back-cross preferable over traditionaldihybrid cross?

9:3:3:1 phenotypic ratio is easier to work with than 1:1:1:1ratio.

Genotypes of the offspring can be determined based on theirphenotype.

If the genes are independently assorted, the dihybrid back-crosswould result in only 2 genotypes in the F1 generation.

B and C

Why do we map genes?

To understand how genes interact with each other

Comparative genomics analysis