Genetic shit

Question 1

Where do gene reside?

Answer 1

The genes for a particular trait reside at a specific

locus (position) on a certain chromosome

Question 2

What is mendel’s first law

Answer 2

Law of Segregation

- The two alleles for each gene seperate

Question 3

What is medel’s second law?

Answer 3

Law of Independent
Assortment
- Alleles of genes on nonhomologus chromosomes assort independently (one does not determine the position of the other

Question 4

What are medel’s laws explained by?

Answer 4

Chromosomal behaviour during meiosis

Question 5

What are the probability rules for offspring calculations

Answer 5

Independant events = x

Mutually exclusive events = +

Question 6

What is a polymorphic trait?

Answer 6

Phenotype controlled by many genes that have

an additive effect

Question 7

What is incomplete Dominance

Answer 7

When F1 has intermediate phenotype

Question 8

What is co dominance?

Answer 8

When both parental phenotypes are present in F1

Question 9

What are some polygenic traits?

Answer 9

skin colour, weight, iq, height

Question 10

What type of distribution of typical of a polygenic trait?

Answer 10

Normal distribution.

- The more genes involved, the higher the number of phenotype classes

Question 11

What other then genetics affects phenotype?

Answer 11

The environment. The Environment smooths differences among phenotypes

Question 12

What are some examples of X linked traits?

Answer 12

Haemophilia, red green colour blindness

Question 13

How do you calculate the recombination frequency?

Answer 13

Recombinants/total outcomes

Question 14

What are linked traits?

Answer 14

They are genes on the same chromosome. They don’t sort independently of each other.

Question 15

Can linked genes be seperated?

Answer 15

Yes via crossing over

Question 16

Are two distant or two close linked genes more likely to be involved in crossing over?

Answer 16

The smaller the distance between two genes - the
less likely a chiasma will be formed between them
- Distant (unlinked) genes have recombination frequencies
around 50% (half recombinant and half parental types).
- Close have a frequency of 0-50%
- There is a linear relationship

Question 17

Why is there bias towards parental phenotypes in some cases?

Answer 17

Fewer recombinants means the 2 genes must be linked (on same chromosome)
(violates Mendel’s 2nd Law (independent assortment))