Biology 1001A Lecture Notes - Lecture 16: Genetic Drift, Allele Frequency, Genetic Recombination

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greenduck439

19 Feb 2016

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They may become harmful or helpful later, as environment. Increases genetic variation, new combinations of alleles through crossing over and independent assortment: reproduction. Reproduction has nothing to do with sex binary fission. Facultatively sexual: can produce genetically identical offspring. When environment is changing/harsh, they reproduce sexually with 2 parents instead of 1. Increases genetic variation, more likely offspring will survive: effect of sex on genetic variation, increases genetic variation through crossing over and independent assortment, types of asexual reproduction, first forms of life reproduced asexually. Most things except plants and animals reproduce asexually. Asexually you can pass 100% of alleles to offspring. Greater chance of extinction due to no genetic variation: mullers ratchet. Deleterious mutations increase over time since there is no way to lose the harmful mutation: types. Fragmentation: types of sexual reproduction (monoecious, dioecious, simultaneous vs. sequential hermaphroditism, humans, plants. Dioecious male and female gametes housed in different individuals (either male or female)

Related Questions

Match the following into these 3 category's: natural selection, genetic drift, gene flow

1. Consistently causes a population to become better adapted to its environment
2, cannot cause a harmful allele to become more common
3. can introduce new allele into a populations gene pool
4. causes allele frequencies to fluctuate rapidly'
5. a result of differential success in reproduction
6 responsible for the founder effect
7. responsible for the bottleneck effect
8., a result of the movement of fertile individuals or their gametes

yellowjackal723

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

What is a genome? What is a genome made of? Describe the bacterial genome. How do bacteria reproduce? What is binary fission? Distinguish between a chromosome and chromatin. Where are chromosomes located in eukaryotic cells? What is the chromosome made of? What is a centromere? What is the centromere's role? What are sister chromatids and how do they arise? Distinguish between somatic cells and germ (gametes) cells. Describe the cell cycle. What are the different phases? What occurs during S phase? What is interphase? How is the cell cycle controlled?

Describe mitosis. What are the phases of mitosis? What occurs in each of the phases of mitosis? What is cytokinesis? How does this differ between plant and animal cells? What is a kinetochore? Where does it form? What is its role? What is the role of microtubules in mitosis? What is a centriole and what is it composed of? What is a centrosome and what is its role in mitosis? What is the metaphase plate and why is this important? What is the mitotic spindle, its role and its makeup? What defines a diploid cell? How many copies of each chromosome is in a diploid cell? What about a haploid cell? Why do the daughter cells of mitosis always have the same complement of chromosomes?

Describe meiosis. What are the phases of meiosis? What occurs in each of the phases of meiosis? Distinguish between meiosis I and meiosis II and describe how each of these processes compare to mitosis. Why do animal cells undergo meiosis? What is a gamete? What is a zygote? What are recombination, crossing-over, and chiasma? When and why does this occur? What is meant by 'homologous pair of chromosomes'? Why don't the daughter cells of meiosis have the same genetic makeup? What controls the segregation of chromosomes into the gametes?

What are genetic characters? What are genetic traits? What is an allele? What is a locus? How many alleles at each locus would a human cell have and why? Distinguish between genotype and phenotype. What is meant by a dominant gene? What is meant by a recessive gene? How do these differ? What is the genotype of a homozygous dominant organism? What is its phenotype? What is the genotype of a homozygous recessive organism? What is its phenotype? What is the genotype of a heterozygous organism? What is its phenotype? What is a genetic cross? Distinguish between the P, F1, and F2 generations. What is a true-breeding line? What is the genotype and phenotype of a cross between homozygous dominant and homozygous recessive parents? If the F1 progeny are crossed, what would be the genotype and phenotype of the F2 generation? What would be the phenotypic ratio? What would be the genotypic ratio? Be ready to generate Punnet square tests or probability analyses of crosses involving more than one genetic locus. Describe a dihybrid cross where two alleles are homozygous dominant in one parent and homozygous recessive in the other. What would be the phenotypic ratio of the F2 generation from this dihybrid cross? What is meant by independent assortment? Be prepared to calculate probabilities resulting from different crosses.

Distinguish between complete and incomplete dominance. How would incomplete dominance alter the results of a hybrid cross? What would the resulting F2 generation phenotype and genotype ratios be? What is codominance? How does this affect the results of crosses? Be prepared to determine likely blood types of parents based on the blood types of their offspring. What is a polygenic trait? What is a carrier state for a genetic disease? What is meant by linked genes? How does this affect expected outcomes of genetic crosses? How is gene linkage used for chromosomal mapping? Distinguish between autosomes and sex chromosomes. What sex chromosomes are found in women? What sex chromosomes are found in men? What are sex-linked traits? Be prepared to give the results of crosses that involve sex-linked recessive traits. What is the process of nondisjunction? What are the likely results? Why is this important? What is a Barr body? Recognize the genetic abnormality of Downs Syndrome, Turner's Syndrome, and Klinefelter's Syndrome.

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Biology 1001A Lecture Notes - Lecture 16: Genetic Drift, Allele Frequency, Genetic Recombination

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