Lec: 16: Evolutionary significance and Genetic Variation

Question 1

Where does variation come from?

Answer 1

1) Mutations
2) Mendel’s laws of segregation and independent assortment
3) Recombination

Question 2

What are mutations?

Answer 2

A stable change in the DNA
Occurs at a low rate
Different possible effects:
Neutral
Deleterious
Beneficial

Question 3

Are mutations directed?

Answer 3

No not towards the environment, environment can effect the rate of mutation, but it is not directing the organisms towards a selective advantage.

Question 4

What is a point mutation?

Answer 4

Change of one base pair in the DNA.

Question 5

What is insertion/ deletions?

Answer 5

Adding or removing one base pair

Question 6

What are changes in repeated number?

Answer 6

REpeating of same pairs in a row.

Question 7

What are chromosomal rearrangements?

Answer 7

flipping of the DNA sequence.

Question 8

Why do humans have more mutations during reproduction than baboons?

Answer 8

One idea is that age at reproduction is the one affecting, more waiting time for birth means more chances of mutations.

Question 9

Does a mutation outside a gene cause more effects than a mutation within a gene?

Answer 9

No, mutation within a gene has more profound efects.

Question 10

What were conclusions from Mendel’s Pea experiment?

Answer 10

1. Inheritance is determined by discreet particles (genes)
2. Each diploid carries two copies of each gene

(alleles can exhibit dominance/recssivity)

3.Gametes fuse to make offspring (Gametes contain only one allele per gene)

4. Offspring inherit one gamete from each parent at random
   (one allele per gene at random sampling)

Question 11

What was mendel’s second law of assortment?

Answer 11

Every gamete is a random sampling of the possible outcomes.

Question 12

What sort of traits did mendel’s law only apply to?

Answer 12

Only discrete traits not the continuous traits,

But..the independent law of assortment applied to complex traits as well, its just there mare many phenotypes playing part.

Question 13

What are quantitative traits affected by?

Answer 13

1) cOMPLEX POLYGENIC (many genes) inheritance

2) Environmental interactions

Question 14

What is the difference between discrete and continious genetic variation?

Answer 14

ContinuousContinious:

1) Quantitative genetics
2) many genes many with small affects, and environment has a affect
3) selection response as a change in average trait value.