BIOL 2299 Lecture Notes - Lecture 4: Genotype Frequency, Allele Frequency, Gene Pool

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indigooyster587

13 Apr 2018

School

Northeastern University

Department

Biology

Course

BIOL 2299

Professor

Anestis

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Document Summary

Genes in populations: populatio(cid:374) ge(cid:374)eti(cid:272)s: stud(cid:455) of ge(cid:374)es a(cid:374)d ge(cid:374)ot(cid:455)pes i(cid:374) a populatio(cid:374, ge(cid:374)e pool: all of the alleles fo(cid:396) e(cid:448)e(cid:396)(cid:455) ge(cid:374)e i(cid:374) a gi(cid:448)e(cid:374) populatio(cid:374) Emphasis is often on variation in alleles between members of a population. We examine a simple genetic locus at which there are two alleles, a and a. If the p and q allele frequencies are known, then the frequencies of the three genotypes may be calculated using the hardy-weinberg equation. In population genetics studies, the hardy-weinberg equation can be used to measure whether the observed genotype frequencies in a population differ from the frequencies predicted by the equation. Evolutionary mechanisms that alter the frequencies of an allele. Natural selection: p(cid:396)o(cid:272)ess i(cid:374) (cid:449)hi(cid:272)h (cid:271)e(cid:374)efi(cid:272)ial t(cid:396)aits that a(cid:396)e he(cid:396)ita(cid:271)le (cid:271)e(cid:272)o(cid:373)e (cid:373)o(cid:396)e (cid:272)o(cid:373)(cid:373)o(cid:374) i(cid:374) successive generations, o(cid:448)e(cid:396) ti(cid:373)e, (cid:374)atu(cid:396)al sele(cid:272)tio(cid:374) (cid:396)esults i(cid:374) adaptatio(cid:374)s. Changes in populations of living organisms that promote their survival and reproduction in a particular environment.

Related Questions

Hardy-Weinberg Equilibrium Problems

p is the frequency of the dominant allele in the population

q is the frequency of the recessive allele in the population

p2 is the frequency of the homozygous dominant genotype

q2 is the frequency of the homozygous recessive genotype

2pq is the frequency of the heterozygous genotype

p + q = 1

p2 + 2pq + q2 = 1 Find q2 ï q ï p ï p2 ï 2pq

A rare disorder of cystic fibrosis (characterized by abnormal transport ofchloride and sodium across an epithelium, leading to thick, viscous secretions) occurs every 1 in 3,300 births. To express this trait one must be homozygous recessive (ff).

The cystic fibrosis allele is represented by f. The normal allele is F. Suppose both parents have alleles Ff. The possible combinations of alleles in the children are FF, Ff, Ff and ff. The alleles ff will cause the disease. So, although the parents do not have cystic fibrosis, they can produce children with the disease. The parents are called 'carriers' of the disease

What is the frequency of the population that carries the trait? (Ff)

A particular gene in a given population of individuals has two alleles, A and a. The frequency of the A allele equals the frequency of the a allele. What are the expected genotype frequencies, assuming the population is in Hardy-Weinberg equilibrium?

	AA = 0.25, Aa = 0.50, aa = 0.25
	AA = 0.5, aa = 0.5
	The answer cannot be determined because the allele frequencies are not provided.
	A = 0.5, a = 0.5

Q1. Which of the following statements is true about the disease Kuru?
Kuru is caused by a virus, which is contracted by eating human brain material.
Kuru is caused by a prion (PrP), which is contracted by eating human brain material.
Kuru is caused by a recessive allele for PrP; if a person has two copies, he or she will develop Kuru.
Kuru is caused by a dominant allele for PrP; if a person has two copies, he or she will develop Kuru.
Kuru is caused by having one copy of the dominant allele and one copy of the recessive allele for PrP.

Q2. True or false: One can calculate the frequency of alleles in a population if the genotypes of the members of the population are known.

True False

Q3. The Hardy-Weinberg equation is p2 + 2pq + q2. In this equation, q2 stands for the frequency of ____________ in a population.

The recessive allele O

ne of the homozygous genotypes

The dominant allele

Heterozygous genotype

Q4. Which of the following descriptions best fits the relationship between the terms gene, allele, locus, and chromosome?

Alleles are different forms of a gene, which can be found at a locus on a chromosome.

Genes are made up of chromosomes, which can be found at a locus on an allele.

Chromosomes are different forms of a gene, which can be found at an allele on a locus.

A locus is made up of alleles, which can be found at a gene on a chromosome.

Q5. Mead and his colleagues proposed a hypothesis for the apparent heterozygote advantage for the PrP locus. What did they suggest as the basis for the high presence of both alleles?
History of cannibalism.
Protection from malaria.
Protection against plague.
They did not propose a heterozygotic advantage for the PrP locus.

Q7. A frog population has two alleles for skin color at the following relative frequencies: Allele SC1= 0.8, Allele SC2 = 0.2. Allele SC2 is:
Dominant
Recessive
Co-dominant
Impossible to determine dominance from the information given.

Q8. A bird population has two alleles for feather color at the following relative frequencies: Allele FC1 = 0.5, Allele FC2 = 0.5. Allele FC1 is:
Dominant
Recessive
Co-dominant
Impossible to determine dominance from the information given.

Q9. Use the following information for both questions 9 and 10: You encounter a few populations of millipedes with variation in skin color. Genotype can be inferred from coloration: CC millipedes are black, Cc millipedes are brown, and cc millipedes are yellow. [You can launch a calculator byclicking here.]

If one millipede population has 60 black individuals, 20 brown individuals, and 20 yellow individuals, what is the relative frequency of allele C in that population?

0.5
0.6
0.7
0.8
Impossible to calculate from the information given.

Q10. If another millipede population's allele frequencies are 0.5 for C and 0.5 for c, what is the expected frequency of the cc genotype in the population, if the population is in Hardy-Weinberg equilibrium?
0.125
0.25
0.5
1.0
Impossible to calculate from the information given.

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BIOL 2299 Lecture Notes - Lecture 4: Genotype Frequency, Allele Frequency, Gene Pool

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