BIOB51H3 Lecture Notes - Lecture 9: Allele Frequency, Genetic Recombination, Polyphenism

20 views4 pages

ochredeer638

25 Aug 2021

School

UTSC

Department

Biological Sciences

Course

BIOB51H3

Professor

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

Document Summary

Ways of change: drift & selection-chapter 6 (lecture notes) Genetic variability in sexual produced offspring is generated during meiosis through: crossing over, genetic recombination, somatic mutations and independent assortment, independent assortment and genetic recombination. Suppose that the sex of the offspring of a species of fish is determined by water temperature. In this case, sex is an example of a: polyphenism, quantitative trait, genetic recombination, genetic polymorphism. Population genetics study of the distribution and frequencies of alleles in populations. Study of how and why allele frequencies change. Population: a group of interacting and potentially interbreeding individuals of the same species. Genetic locus: location of a specific gene or sequence of dna on a chromosome. Homozygous: individual carries two copies of the same allele at a locus. Heterozygous: individual carries different alleles at a locus. Evolution: change in allele frequencies from one generation to the next.

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

What type of daughter cells are produced during meiosis?

A. genetically distinct due to crossing over

B. genetically identical to the mother cell

C. genetically identical to each other

D. genetically aneuploids

What is NOT a benefit of asexual reproduction compared to sexual reproduction?

A. The offspring will be as successful in the habitat as the parent.

B. all members of the population can reproduce themselves

C. The only source of variation in the next generation is mutation.

D. They do not require another organism of the opposite sex.

In what phase of meiosis does Independent assortment of homologous chromosomes occur?

A. meiosis I

B. interphase

C. cytokinesis

D. meiosis II

In what phase of meiosis does Independent assortment of homologous chromosomes occur?

A. meiosis I

B. interphase

C. cytokinesis

D. meiosis II

Need help with evolution questions:

1.) A haplotype is best defined as the ________________.

	haploid genotypes of all the gametes produced by a diploid individual

ABO blood type conferred by an individual gamete

genotype of either the paternal or maternal chromosomal complement

multilocus genotype of a chromosome or gamete

2.) Which of the following statements regarding linkage disequilibrium is true?

Exists when D is less than zero, but not when it is greater than zero.

Is reduced by sexual reproduction.

Is increased by crossing-over during meiosis.

Is increased by any random sampling error that happens to create or destroy certain chromosome genotypes but not others.

Is reduced by selection that favors certain combinations of genotypes.

3.) Selection on multilocus genotypes in random-mating populations leads to linkage disequilibrium when _______________.

it reduces mutation rates

it eliminates all haplotypes from the population

it prevents crossing-over during meiosis

some allele combinations confer greater fitness than do others

4.) When two loci are in linkage equilibrium, the allele carried on a chromosome at one locus is independent of the allele carried on the chromosome at another locus. When this is the case, _________________.

allele frequencies will not change over time

the two loci (or, more specifically, their protein products) do not interact

the frequency of each haplotype can be calculated by multiplying the frequency of its two alleles

all possible haplotypes occur at equal frequency

5.) Which of the following accurately characterize(s) Muller's ratchet model for the selective advantage of sexual reproduction?

Drift establishes linkage disequilibrium because multilocus genotypes with few mutations are eliminated by chance events.

In populations without sexual reproduction, deleterious mutations accumulate, eventually imposing such a burden that the population goes extinct.

Sex is favored selectively because it recreates the zero-mutation genotypes lost due to drift.

All of the above correctly characterize Muller's ratchet model for the evolution of sexual reproduction.

6.) The genetic signature of recent positive selection on a locus is _______________.

high frequency and low linkage disequilibrium

low frequency and low linkage disequilibrium

low frequency and high linkage disequilibrium

high frequency and high linkage disequilibrium

7.) Sexual reproduction is advantageous both in changing environments and in constant environments, compared to asexual reproduction.

True

False

8.) Sexual reproduction causes genetic recombination via crossing-over, which combines genotypes from different parents.

True

False

9.) One reason sex may be maintained in natural populations is proposed by the "Red Queen Hypothesis", which states that.....

genotypes created by sex are created by natural selection over and over

recombination creating novel genotypes that can resist infection by parasites

mutation load is reduced by novel adaptive mutations

the ability of sex to fix multiple

BIOB51H3 Lecture Notes - Lecture 9: Allele Frequency, Genetic Recombination, Polyphenism

Document Summary

Get access

Related Documents

BIOB51H3 Lecture Notes - Lecture 17: Genetic Load, Mate Choice, Parental Investment

BIOB51H3 Lecture Notes - Lecture 17: Asexual Reproduction, Genetic Load, Spermatophore

BIOB51H3 Lecture Notes - Lecture 16: Sequential Hermaphroditism, Genetic Load, Amphiprioninae

Related Questions