Genes in populations

Question 1

what are causes of mutations in genes?

Answer 1

radiation, UV, X ray

Question 2

what is the source of all genetic variation?

Answer 2

mutation

Question 3

what is polyploidy?

Answer 3

3 or more times the haploid chromosome number

Question 4

what is aneuploidy?

Answer 4

one set of chromosomes is incomplete

Question 5

what is nullisomy and its effects?

Answer 5

both members of a pair of chromosomes are missing and it is lethal

Question 6

what are translocations?

Answer 6

exchange of parts between non homologous chromosomes

Question 7

what is an inversion and its effect?

Answer 7

a balanced rearrangement often with no effect only maybe in meiosis

Question 8

what is the difference between synonymous and non-synonymous mutations?

Answer 8

synonymous dont change the amino acid and non synonymous do

Question 9

what are features of gametic mutations?

Answer 9

heritable, severe and can affect all cells

Question 10

what are features of somatic mutations?

Answer 10

not heritable, usually mild and don’t affect all cells

Question 11

what are mendels 3 laws?

Answer 11

1) the law of segregation
2) the law if independent assortment
3) the law of dominance

Question 12

what is the law of segregation?

Answer 12

two parts of a gene segregate from each other during the formation of gametes

Question 13

what is the law of independent assortment?

Answer 13

the alleles of different genes segregate independently of each other

Question 14

what are exceptions to the law of independent assortment?

Answer 14

the closer 2 genes physically are to each other the greater violation of the law

Question 15

what are the 3 reasons why natural selection works?

Answer 15

1) individuals vary genetically
2) some variants are fitter than others
3) variation is heritable

Question 16

what does blending inheritance cause?

Answer 16

all the offspring are the same - geneticaly uniform population

Question 17

what is is it called if one gene is involved in a disease?

Answer 17

mendelian/monogenic disease

Question 18

what is it called if more than one gene is involved in a disease?

Answer 18

multi factual disease

Question 19

what is autosomal dominance?

Answer 19

• affected person has at least one affected parent and can affect either sex

Question 20

what is autosomal recessive?

Answer 20

• affected person usually have unaffected parents and can affect either sex

Question 21

what is x linked recessive?

Answer 21

carrier females which usually have male affected offspring

Question 22

what is x linked dominant?

Answer 22

affects both males and females - all females of affected males have the disease

Question 23

what is y linked disease?

Answer 23

only males are affected

Question 24

what is X chromosome inactivation? (lyonization)

Answer 24

in each cell of females one X is randomly inactivated

Question 25

what did the fruit fly experiments demonstrate?

Answer 25

shows that many genes lie on chromosomes - showed eye colour gene was on X chromosome

Question 26

what is recombination? (crossing over)

Answer 26

non independent assortment of linked genes

Question 27

how do you work out a recombination fraction?

Answer 27

add together the observed recombinant genotypes and divide by total of all genotypes

Question 28

what does the recombination fraction measure?

Answer 28

the distance between 2 genes

Question 29

what is the unit of measurement to measure distance between genes?

Answer 29

centimorgans

Question 30

what is the evolutionary significance of recombination?

Answer 30

can speed up the rate of evolution producing fitter genotypes and can break up co adaptive gene combinations