4.4.1- Genetic diversity

Question 1

How is genetic diversity increased in a population?

Answer 1

1- Mutations

2- Gene flow ( intro of new alleles by migration)

Question 2

What is an allele?

Answer 2

Different forms of a particular gene,
found at the same locus (position) on a
chromosome. A single gene could have
many alleles

Question 3

Define genetic diversity.

Answer 3

The total number of different alleles in a

population.

Question 4

What advantage does a high genetic

diversity provide?

Answer 4

Ability to adapt to a change in
environment; allows natural selection to
occur.

Question 5

The scientists obtained DNA from otters that were alive before hunting started.
Suggest one source of this DNA.

Answer 5

Bone / skin / preserved remains / museums.

Question 6

What can you conclude about the effect of hunting on genetic diversity in otters?
Use data from the figure above to support your answer.

Answer 6

1. (Hunting) reduced population size(s), so (much) only few alleles left;
   Accept bottleneck
2. Otters today from one / few surviving population(s);
   Accept founder effect
3. Inbreeding.
   Allow any two

Question 7

Some populations of animals that have never been hunted show very low levels of
genetic diversity.
Other than hunting, suggest two reasons why populations might show very low
levels of genetic diversity.

Answer 7

1. Population might have been very small / genetic bottleneck;
2. Population might have started with small number of individuals / by one
   pregnant female / founder effect;
3. Inbreeding.
   Allow any two

Question 8

What is the name of a position of a gene on a chromosome? (1)

Answer 8

Locus/loci

Question 9

What do these data show about the differences in genetic diversity between these breeds of dog? (3)

Answer 9

1. Jack Russel genetic diversity is the greatest
2. Bull terrier genetic diversity is the smallest / most inbred
3. Miniature terrier and Airedale terriers are similar
4. Standard deviations do not overlap / do overlap with correct ref to significance

Question 10

miniature terriers were first bred from bull terriers in the 19th century

suggest 1 explanation for this observed difference in genetic diversity between miniature terriers and bull terriers (2)

Answer 10

1. (Bull terrier) breeding has included a genetic bottleneck/ small population/more inbreeding/ greater
   selection (pressure);

Accept: founder effect

2. Reduced number of different alleles/size of gene pool;

Reject: decrease in number of genes

Ignore ref to mutations

OR

3. Miniature (terrier) breeding has included more outbreeding/less selection (pressure);
4. Increased number of different alleles/larger gene pool/more variety of alleles;

Reject if genes used instead of alleles

Reject: lower frequency of alleles Ignore ref to mutations