BIO 198 Chapter Notes - Chapter 5: Genetic Linkage, Mendelian Inheritance, Synteny

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silverbee937

30 Sep 2017

School

University of Rochester

Department

Biology

Course

BIO 198

Professor

Cia

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Document Summary

5. 1 linked genes do not assort independently. Syntenic genes genes that are located on the same chromosome; can assort independently if they are far enough away from each other on the same chromosome due the crossing over. Recombinant chromosomes when the alleles of syntenic genes are reshuffled by crossing over between homologous chromosomes. Parental (non-recombinant) chromosomes the chromosomes that do not have their alleles reshuffled by cross over. Genetic linkage mapping the use of genetic linkage to determine the positions of genes on chromosomes. The discovery of genetic linkage: william bateson studied the traits of flower color and pollen grain shape separately and together. He saw that separately they behaved like mendelian genetics deemed them to work (3:1). Yet, when he looked at them together, they had much more parental phenotypes than expected: morgan also found similar ratios when working with fly eye color and wing size.

Related Questions

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.

Please help me with these two!

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