BIO 370 Study Guide - Quiz Guide: Oldfield Mouse, Haplotype, Allele Frequency
BIO370 Evolution - Spring 2018 Discussion Week 5
Name: Anh Nguyen Group # UTEID ann762
1. Defie latet ariatio. (tip: ou a gie the eplaatio draig a graph, ut do’t forget to
label the axis and comment what is illustrated)
-There is too much Mendelian variation for all the genotypes to be represented in one
generation, so it comes up in a couple generations later. With the help of genetic reassortment,
new phenotypes can be present from previous variation, as well as selection can shift allele
frequencies.
2. What is a polygenic trait? What is epistasis? Give examples of both and explain how
phenotype is affected by additive and non-additive interaction of loci.
-Polygenic trait – a trait affected by multiple genes at the same time.
-Epistasis – alleles at 2+ loci interact nonadditively.
-Example of additive interaction of loci – skin color, the more melanin you have the
darker your skin color.
-Example of non-additive interaction of loci – oldfield mouse, when homozygous for dark
Agouti allele then the effects of Mc1R locus are masked, resulting in fully dark color. When one
copy of the light Agouti allele is expressed, then the effects of Mc1R locus is shown.
3. What is haplotype? How do physically linked alleles segregate and how does it affect
haplotype frequencies? Why is it important to calculate allele frequencies under Hardy-
Weinberg model?
-Haplotype – a set of alleles, with only one at each locus under consideration; a set of
gene copies along one particular chromosome.
-Physically linked alleles segregate together, and without recombination a double
heterozygote will produce 2 gamete types. With recombination, will form 4 gamete types.
-Important to calculate allele frequencies under HW model because HW frequency of
each genotype is equal to the chance that 2 gametes are drawn randomly from the population
that makes up the genotype, in which the chance is just the product of allele frequencies of two
alleles that make up that genotype.
4. Define the terms of the formula below. When is D going to be equal to zero? What represents
D with a positive value? What represents D with a negative value?
D = hABhab - haBhAb
-D will be 0 when alleles at each locus occur independently.
-hAB = frequency of AB haplotype
-hab = frequency of ab haplotype
-haB = frequency of aB haplotype
-hAb = frequency of Ab haplotype
5. In 1992, Spolsky, Phillips, and Uzzell reported genetic evidence that asexually reproducing
lineages of a salamander species have persisted for about 5 million years. Is this surprising? Why
or why not? Speculate about what sort of environment these asexual salamanders live in, and
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
There is too much mendelian variation for all the genotypes to be represented in one. Polygenic trait a trait affected by multiple genes at the same time. Epistasis alleles at 2+ loci interact nonadditively. Give examples of both and explain how phenotype is affected by additive and non-additive interaction of loci. darker your skin color. Example of non-additive interaction of loci oldfield mouse, when homozygous for dark. Agouti allele then the effects of mc1r locus are masked, resulting in fully dark color. Why is it important to calculate allele frequencies under hardy- Weinberg model? gene copies along one particular chromosome. heterozygote will produce 2 gamete types. Important to calculate allele frequencies under hw model because hw frequency of. Haplotype a set of alleles, with only one at each locus under consideration; a set of. Physically linked alleles segregate together, and without recombination a double. D will be 0 when alleles at each locus occur independently.
