Lesson test: Populations and frequencies

Sign in

Libre University uses your GitHub account. Signing in is only needed to sit a final test, so the score is kept on your profile.

Populations and frequencies

1.[3p]
What was the error in Yule's question about brachydactyly?

He read the 3:1 ratio, which describes one particular cross, as a statement about a whole population

Correct

He assumed brachydactyly is recessive when it is dominant

The answer is: He read the 3:1 ratio, which describes one particular cross, as a statement about a whole population

He used a sample too small to detect the effect

The answer is: He read the 3:1 ratio, which describes one particular cross, as a statement about a whole population

He confused genotype frequencies with genotype counts

The answer is: He read the 3:1 ratio, which describes one particular cross, as a statement about a whole population

2.[2p]
Which is the important half of the Hardy-Weinberg result?

That the allele frequency in the next generation is unchanged

Correct

That genotypes occur as $p^{2} : 2 p q : q^{2}$

The answer is: That the allele frequency in the next generation is unchanged

That dominant alleles are three times as common as recessives

The answer is: That the allele frequency in the next generation is unchanged

That mating must be at random

The answer is: That the allele frequency in the next generation is unchanged

3.[3p]
Cystic fibrosis affects about one in 2,500 births. What is the carrier frequency as a percentage?

CorrectNot quite: 3.92

4.[3p]
Phenylketonuria affects about one in 10,000 births. How many carriers are there per affected person?

CorrectNot quite: 198

5.[2p]
An individual organism evolves over its lifetime, under the definition this lesson gives.

True

The answer is: False

False

Correct

6.[3p]
Which assumptions must hold for genotype frequencies to sit at $p^{2} : 2 p q : q^{2}$ with $p$ unchanging?

Select all that apply

Mating is at random with respect to the locus

Correct

The population is large enough to ignore sampling error

Correct

No selection, mutation or migration acts at the locus

Correct

The two alleles are equally frequent

The answer is: Mating is at random with respect to the locus, The population is large enough to ignore sampling error, No selection, mutation or migration acts at the locus

7.[3p]
A sample of 1,000 people gives 298 $M M$ , 489 $M N$ and 213 $N N$ . What is the frequency of the $M$ allele?

CorrectNot quite: 0.5425

8.[3p]
A sample shows an excess of both homozygotes and a deficit of heterozygotes. What is the commonest explanation in practice?

A null allele that fails to amplify, so heterozygotes are scored as homozygotes

Correct

Selection favouring both homozygotes

The answer is: A null allele that fails to amplify, so heterozygotes are scored as homozygotes

Mutation at the locus

The answer is: A null allele that fails to amplify, so heterozygotes are scored as homozygotes

Migration into the population

The answer is: A null allele that fails to amplify, so heterozygotes are scored as homozygotes

9.[2p]
A character is set by six loci, each with an adding and a non-adding allele. How many phenotypic classes are there?

CorrectNot quite: 13

1.[3p] What was the error in Yule's question about brachydactyly?

2.[2p] Which is the important half of the Hardy-Weinberg result?

3.[3p] Cystic fibrosis affects about one in 2,500 births. What is the carrier frequency as a percentage?

4.[3p] Phenylketonuria affects about one in 10,000 births. How many carriers are there per affected person?

5.[2p] An individual organism evolves over its lifetime, under the definition this lesson gives.

6.[3p] Which assumptions must hold for genotype frequencies to sit at p2:2pq:q2 with p unchanging?

7.[3p] A sample of 1,000 people gives 298 MM, 489 MN and 213 NN. What is the frequency of the M allele?

8.[3p] A sample shows an excess of both homozygotes and a deficit of heterozygotes. What is the commonest explanation in practice?

9.[2p] A character is set by six loci, each with an adding and a non-adding allele. How many phenotypic classes are there?

1.[3p]
What was the error in Yule's question about brachydactyly?

2.[2p]
Which is the important half of the Hardy-Weinberg result?

3.[3p]
Cystic fibrosis affects about one in 2,500 births. What is the carrier frequency as a percentage?

4.[3p]
Phenylketonuria affects about one in 10,000 births. How many carriers are there per affected person?

5.[2p]
An individual organism evolves over its lifetime, under the definition this lesson gives.

6.[3p]
Which assumptions must hold for genotype frequencies to sit at $p^{2} : 2 p q : q^{2}$ with $p$ unchanging?

7.[3p]
A sample of 1,000 people gives 298 $M M$ , 489 $M N$ and 213 $N N$ . What is the frequency of the $M$ allele?

8.[3p]
A sample shows an excess of both homozygotes and a deficit of heterozygotes. What is the commonest explanation in practice?

9.[2p]
A character is set by six loci, each with an adding and a non-adding allele. How many phenotypic classes are there?