BIOL 103 Lecture Notes - Sexual Reproduction, Genetic Variation, Gamete

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grayweasel585

14 Apr 2014

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Document Summary

Phenotype: physical expression of a genotype; observable characteristics on an individual resulting from the interaction of its genotype with the environment. Genotype: genetic constitution of an individual organism. Allele: one or two more alternate forms of a gene that arise by mutation and are found at the. Locus (plural loci): the specific location of a gene or dna on a chromosome same place on the chromosome. Dominant allele: allele that produces same phenotype whether its paired allele is identical or different. Recessive allele: allele that produces it"s phenotype only when it is paired with an identical allele. Homozygous: having identical alleles at corresponding loci. Heterozygous: having dissimilar alleles at corresponding loci. Evolution of populations is best understood in terms of: Mutations (eg. uv light on skin cells: changes in dna sequences lead to new alleles, cannot enter population unless in gametes. Sexual reproduction variable gametes: meiosis shuffles maternal/paternal chromosomes to new combinations.

Related Questions

QUESTION 1

Jim is blood type A, his brother John is type O and his sister Jane is type AB. What are the genotypes of their parents?

Which of the following is true for alleles that show incomplete dominance?

Heterozygotes have a genotype like the dominant allele.

Homozygotes have a genotype like the recessive allele.

Heterozygotes have a phenotype intermediate between the dominant and recessive alleles.

Homozygotes have the same phenotype as the heterozygotes.

QUESTION 3

Which principle of inheritance concluded that when games are formed in meiosis, the two alleles of each gene separate from one another, and each gamete receives only one allele?

independent assortment

Which term best describes a condition in which alleles at one locus can alter the expression of alleles at another locus?

polygenic inheritance

A single unit of genetic information located on a chromosome defines:

The physical expression (appearance or function) of an organism's genes defines:

genotype

a single characteristic

Palomino horses (golden color with a blond mane) are an incompletely dominant trait produced by the combination of the chestnut color allele and the cream color allele. If you wanted to produce as many palominos as possible, which mating strategy below would be the best choice?

Which term best describes the effect of a single gene on multiple aspects of the phenotype?

polygenic inheritance

QUESTION 9

Which term best describes the separate expression of both alleles for a single trait in the same cell?

polygenic inheritance

QUESTION 10

One form of a gene found on a single chromosome defines:

A chocolate lab (whose mother was a yellow lab) is mated with a black lab whose genotype is BbEe. What fraction of the offspring would be expected to be yellow labs?

What type of allele is always expressed regardless of whether the individual is homozygous or heterozygous for it?

Both the dominant and recessive alleles

Given the parents AABBGgHhrr Ã AabbGgHhRr, assume simple dominance and independent assortment. What proportion of the progeny will be expected to have the genotype AaBbggHHrr?

___________________ is defined as having two of the same type of allele for a particular trait.

The physical position of an allele on a single chromosome defines:

Which term best describes two or more genes affecting the phenotype in an additive fashion?

codominance

polygenic inheritance

2. Consider two gene loci in the mouse, locus1 and locus 2. Each locus is on a different, nonhomologousautosomal chromosome . Alleles at locus 1 influence fur color.Allele A is for black and allele a is for white.Allele A is completely dominant to allele a . Allelesat locus 2 influence stature; allele B is for tall andallele b is for short. Allele B is completelydominant to allele b.

Mouse 1, genotype Aa Bb, mates withfemale mice , genotype Aa Bb; 100 progeny are produced.

___: What fraction of the gametes from mouse 1is expected to be genotype Ab ?

___: What fraction of the gametes from mouse 1is expected to have allele a ?

___: What fraction of the progeny is expectedto be true-breeding for both stature and black fur?

___: How many progeny are expected to be tallwith white fur? Show your calculations.

___: How many progeny are expected to beheterozygous at both loci? Show yourcalculations.

___: If you randomly choose two progeny mice,one at a time, what is the probability that both mice are tall andwhite? Show your calculations.

3. Using the geneloci, alleles and phenotypes as described in question 2, considerthis mating between Mouse 3, black and tall, and mouse 4, black andtall. That mating produced these progeny: 58 black and short, 165black and tall, 25 white and short, 62 white and tall.

____: what is the expectednumber of progeny of the phenotypic class, black and short?Show your work.

____: What is the Chi-squarevalue for these observed and expected data? Show yourwork.

___: How many degrees offreedom are used for the Chi-square test in thissituation?

______: What is theapproximate Chi-square probability for this Chi-square value anddegrees of freedom?

_____: Mouse 3 mated withmice that had the phenotype short & white, and produced 200progeny. How many progeny are expected to have the phenotype, blackand tall?

____: In addition tothe gene loci, alleles and phenotypes described in question 1,consider a third gene locus with alleles D and d; D for long fur,and d for short fur. D is completely dominant to allele d. Thisgene locus segregates independently of the other two loci. Mouse 5,genotype Aa Bb Dd, mates with mouse 6 of the same genotype.What fraction of the progeny are expected to have the phenotype,black fur, tall & long fur?

I don't need the answers to question #2, justquestion #3. (the hilghted) However question 3 asks for informationfrom question 2, so that is why it is there

Thank you