Forms of variation of genes in a population

Question 1

What is the hardy wineburg equ

Answer 1

Q^2 + 2pq + P^2 = 1
p+q=1

Question 2

If a proportioin of the popultion has a genetic disease (1/2500) how to work out nb of carriers

Answer 2

Q^2 = 1/2500 therefore Q = 1/50=0.02
p=1-0.02=/98
2pq=nb of carriers = 20.980.02

Question 3

if the number of x chromosomes with a defect is 0.1 what proportion of men vs woman will exspress the disease

Answer 3

men = 0.1 *100
women = 0.1^2 *100

Question 4

Describe how stabilizing selection effects a population

Answer 4

Stabilising selction favors the middle allele, this type of selection disfavors either extream case

Question 4

descibe how disruptive selection affects a population

Answer 4

disruptive selection is when the middle phnotype is not favored and being at one of the two extreams gives a better chance of survival

Question 4

Describe how directional selection affects a population

Answer 4

directional selection skews towards one allele or the other moving the median towards having a specific phenotype of the other making this more common

Question 5

What are the five types of selection

Answer 5

stabilising selection
directional selection
disruptive selection
frequency dependant selection
sexual selection

Question 6

descibe how sexual selection affects a population

Answer 6

sexual selection is when having a phenotype means you are more likely to reproduce causing more of this trait to be present in the population

Question 7

describe how frequency dependant selection affects a population

Answer 7

Being rare is advantagous causes this rare gene to reproduce more, in the next generation this trait is now more common so the previously more common trait is rare. this flips back and fourth.

Question 8

what is the effect of migration on a population

Answer 8

increased genetic diversity
change in the population size
change in the % of the exsiting alleles
brings the two groups close together

Question 9

What is a cline

Answer 9

a cline is the effect of a change in the presense of phenotype over geographical area.
Could be due to
climate, soil type, water temprature

Question 10

What is the exsepected recombinent frequency for unlinked vs linked genes

Answer 10

unlinked around 50%
linked, 0-50
the smaller the recombinenet frequency the closer of the chromosome the alleles are

Question 11

What is the founder effect

Answer 11

When some individuals from a population establish a new population elsewhere. the new population will have a much smaller pool of alleles and therefore less genetic diversity

Question 12

What are effects/causes of allele frequencys varry in a population

Answer 12

non random mating - inbreeding or assortive mating (breeding with simlar looking people)
Random genetic drift
bottle neck effect
the founder
effect natural selection
gene flow or migration

Question 13

Why is mutation not a good way that allele frequency change

Answer 13

It is a very slow form of allele frequency change, more linked to evolution

Question 14

Describe random genetic drift and the bottleneck affect

Answer 14

Random genetic drift is when random events cause the change in percentages of an allele across a population, impacts smaller communities more greatly

The bottlneck effect is when an external sorce causes a large reduction in the number of an allele in a population