7.1 INHERITANCE

Question 1

What is the genotype?

Answer 1

The genetic make up of an organism. All the alleles it contains.

Question 2

What is the phenotype?

Answer 2

Observable characteristic of an organism, which is a result of the interaction between the environment and genetics.

Question 3

What is an allele?

Answer 3

A version of a gene. Diploid organisms always have 2 alleles per gene, one from each parent.

Question 4

What are the types of alleles?

Answer 4

• Dominant
• Recessive
• Co-dominant

Question 5

What is the F0 generation?

Answer 5

The products of pure breeds (homozygous recessive/dominant)

Question 6

What is the F1 generation?

Answer 6

The products of F0 x F0 (heterozygous)

Question 7

What is the F2 generation?

Answer 7

The products of F1 x F1

Question 8

What are co-dominant alleles?

Answer 8

When both alleles are expressed because they are both dominant.

Question 9

What is an example of when multiple alleles are present in genetics?

Answer 9

Blood Type (AB/O/A/B)

Question 10

Which blood groups are co-dominant?

Answer 10

Ia & Ib

Question 11

Which blood groups are recessive?

Answer 11

O

Question 12

What is sex linkage?

Answer 12

When certain genes can only be carried on the X or Y chromosomes.

Question 13

Why do mainly men exhibit X linked diseases?

Answer 13

• X linked diseases are recessive.
• Men have XY and women have XX.
• Men only need one recessive allele to have the disease whereas women need 2.
• Much more likely for men to have the X-linked disease.

Question 14

If a male has an X linked disease, which parent did he get it from?

Answer 14

The mother has to be a carrier, so he gets it from his mother.

Question 15

What is an autosome?

Answer 15

All the chromosomes that aren’t sex chromosomes.

Question 16

What is autosomal linkage?

Answer 16

When multiple genes appear on the same chromosome, so are linked in inheritance.

• Linked genes stay together, and are passed in together.

Question 17

How does autosomal linkage come about?

Answer 17

The too genes are too close together on the chromosome, so don’t split during crossing over. This means they stay together on their chromosome.

Question 18

What is epistasis?

Answer 18

When the allele of one gene masks the expression of another allele in the phenotype.

Question 19

What is recessive epistasis?

Answer 19

When a recessive allele masks another (9:3:4 ratio)

Question 20

What is dominant epistasis?

Answer 20

When a dominant allele masks another (12:3:1)

Question 21

What is chi-squared?

Answer 21

A statistical test that shows whether the differences between observed and expected results are significant.

Question 22

What are the criteria when carrying out chi-squared?

Answer 22

1. Big sample size (n>20)
2. Only works for discrete data.
3. Can only use raw, unprocessed no. counts.

Question 23

How do you find chi-squared?

Answer 23

x² = the sum of [ (O-E)²/E]

O = observed number
E = expected number