BIO 182 Chapter Notes - Chapter 17.3, 15.1, 18.1: Noncoding Dna, Normal Distribution, Genetic Distance

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greyhare699

18 Sep 2016

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Document Summary

Linked genes are those that are close together on the same chromosome: do not assort independently, tend to be transmitted together. Sex-linked genes on the x chromosome more commonly affect males since only the mother has to pass it on. Nonrecombinants same allelic combination as in the parent. Crossing over can result in nonrecombinant chromosomes if a second crossover occurs that reverses the effects of the first. Farther apart chromosomes have a higher chance of being crossed over separately. Frequency of recombination proportion of recombinant chromosomes which is a measure of genetic distance between genes. Genetic map diagram showing relative position of genes along a chromosome. Map unit distance between genes resulting in 1% recombination. Genetic variation genetic difference between individuals of a population. Populations with larger gene pools have more variation. Alleles different forms of a gene. Homozygous an individual with two of the same alleles. Heterozygous an individual with two different alleles.

Related Questions

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

To determine the genotype of an organism

All of the above

coralox210

The syntenic genes A and Z are linked. A cross between two parents, AAzz and aaZZ, produces F₁ progeny with the AaZz genotype. What are the possible arrangements of alleles on the F₁ progeny's chromosomes?

A/Z or a/z

The answer is not AZ/az

Genes that are on the same chromosome can assort independently when

they are very close together on a chromosome and crossing over occurs rarely between the genes.

they are far apart on a chromosome and crossing over occurs rarely between the genes.

they are far apart on a chromosome and crossing over occurs frequently between the genes.

they are syntenic.

Genes on the same chromosome cannot assort independently.