BIOL 1090 Lecture Notes - Lecture 5: Punnett Square, Mendelian Inheritance, Telophase

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5 Mar 2016

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Applications of mendal"s principles: mendal"s principle of segregation is analyzed in telophase ii when each allele is recovered in half the products of meiosis. Outcomes of a monohybrid cross with a punnett square. 1 gene with 2 alleles = 2 possible haploid genotypes (gametes) 2 different gametes from each of two parents = 4 possible diploid genotypes. Outcomes of a dihybrid cross with a punnet square. For 2 genes = 4 possible haploid genotypes (gametes) 4 different gametes from each of two parents = 42 = 16 possible diploid genotypes: mendal"s principle of independent assortment combinations of chromosomes and alleles is recovered in one-fourth of the products of meiosis (telophase ii). Crossing over does not influence the frequency of gametes for independently assorting genes. General rules: n = number of genes, n = 2n possible haploid genotypes (gametes, the further apart the genes are on a chromosome, the more likely they will assort independently.

Related Questions

Question 1 Select one answer. 10 points Crossing over occurs:_______________.

during both meiosis I and meiosis II

during mitosis but not meiosis

during meiosis II only

during meiosis I only

Question 2 Select one answer. 10 points Homologous pairs ofchromosomes line up at the center of the cell in during which stageof meiosis?

Metaphase I,

Metaphase II,

Telophase I,

Telophase II

Question 3 Select one answer. 10 points A haploid organism hashow many copies of each chromosome?

1, 2, 3, 4

Question 4 Select one answer. 10 points The sister chromatidsseparate during which stage of meiosis?

Anaphase I, Anaphase II, Prophase I, Prophase II

Question 5 Select one answer. 10 points Describe the importanceof independent assortment: ________________________.

will assort independently of each other,

will sort to the same gamete,

are called alleles

All of these are true

Question 6 Select one answer. 10 points How many differentgametes are produced by a cell with the genotype AABb?

1, 2, 3,4

Question 7 Select one answer. 10 points The next two questionsare based on the following information. Part 1 of 2: In beansyellow (Y) is dominant to green (y) and smooth (S) is dominant towrinkled (s). What are the possible genotypes for the offspring ofthe following cross: YySS and YYSs.

Yy, SS, YY, Ss

YYSS, YySS, YYSs, YySs

YYSS, YYss, yySS, yyss

YS, yS, YS, yS

Question 8 Select one answer. 10 points Part 2 of 2: In beanswith yellow (Y) dominant to green (y) and smooth (S) dominant towrinkled (s): What are the phenotypes for the offspring in theexample in the previous question?

100% green wrinkled,

50% yellow smooth and 50% greensmooth,

100% yellow smooth,

50% yellow smooth and 50% yellowwrinkled

Question 9 Select one answer. 10 points Alleles are differentversions of a _______________.

chromosome,

genotype,

phenotype,

gene

pucesnake469

1. What is the chromosome theory of inheritance?

2. Understand how independent assortment can cause gametes to have four combinations of alleles when an individual is heterozygous for two genes on two different chromosomes.

3. What are linked characters and linked genes? Understand why linked genes will not independently assort.

4. How can crossing over affect linked genes?

5. What are recombinant gametes?

6. Define recombinant frequency. Be able to use the recombinant frequency to determine how close two genes are on a chromosome.

7. What is a linkage map?

8. What is the function of the SRY gene on the Y chromosome? What happens if you don't have this gene?

9. Know how sex is determined in mammals, birds, bees and ants, and reptiles.

10. How many autosomes and sex chromosomes do normal human haploid and diploid cells have?

11. What does it mean for a gene to be X-linked or Y-linked?

12. Be able to answer word problems and fill out a Punnet square involving an X-linked recessive trait.

13. Which sex is more likely to have an X-linked recessive disorder? Understand why.

P.s The most simple answer would be preferable. I would be copping the notes over that you will provide to my noteb book and add my details to it.

greylocust179

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

BIOL 1090 Lecture Notes - Lecture 5: Punnett Square, Mendelian Inheritance, Telophase

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