6.1.2 Patterns in inheritance

Question 1

Monohybrid inheritance

Answer 1

one gene has 2 alleles

Question 2

allele

Answer 2

different form of the same gene

Question 3

homozygous dominant

Answer 3

2 dominant alleles

Question 4

homozygous reccessive

Answer 4

2 reccessive alleles

Question 5

Codominance

Answer 5

more than one dominant allele

Question 6

when does codominance occur

Answer 6

when 2 different alleles for a gene are equally dominant

Question 7

Multiple alleles

Answer 7

one gene but more than 2 alleles

Question 8

example of a multiple allele

Answer 8

human blood group

Question 9

Sex linkage

Answer 9

when a gene is found on the sex chromosome
genes found on X and Y chromosome

Question 10

Autosomal linkage

Answer 10

inheritance of 2 genes on same chromosome except a sex chromosome inherited together not independently assorted

Question 11

Dihybrid inheritance

Answer 11

2 genes on different chromosomes
no link
each gene has 2+ alleles

Question 12

Epistasis

Answer 12

interaction of different gene loci so one gene locus masks or supresses the expression of another gene locus
changes the expected ratios

Question 13

Reccessive Epistasis

Answer 13

reccessive alleles presence affect another locus

Question 14

epistasis by complementary action

Answer 14

Alleles needed on both genes for correct expression
9:7 ratio

Question 15

types of speciation

Answer 15

directional selection
stabilising selection
distruptive selection

Question 16

directional selection

Answer 16

change in enviroment
changes the selection pressure and frequency of different alleles in gene pool change

Question 17

stabalising selection

Answer 17

selection pressure move inwards
leads to reduction in the range of variation within population
no change in mode

Question 18

disruptive selection

Answer 18

acts against mode favouring the extreme
produces bimodal distrubution with 2 groups of phenotypes
may produce 2 distinct forms of species
new species form over long period of time

Question 19

Hardy Weinburg Principle

Answer 19

frequency of alleles in a population remains constant over time so long as five key conditions about the populations were met

Question 20

Epectations for Hardy Weinburg principle to work

Answer 20

no mutations
no immigration/emigration
no selection
mating is random
population is large

Question 21

why can’t there be any mutations

Answer 21

so no new alleles are created

Question 22

why no immigration or emigration

Answer 22

so no new alleles are introduced or lost

Question 23

why no selection

Answer 23

so no alleles are formed or eliminated

Question 24

why must mating be random

Answer 24

alleles are mixed randomly

Question 25

why must population be large

Answer 25

so theres no genetic bottlenecks

Question 26

why is the Hardy Weinberg principle not very good

Answer 26

its an unrealistic expectation of a population

Question 27

Equations for Hardy Weinburg principle

Answer 27

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

Question 28

p^2

Answer 28

frequency of AA

Question 29

2pq

Answer 29

frequency of Aa

Question 30

q^2

Answer 30

frequency of aa

Question 31

p

Answer 31

frequency of dominant allele A

Question 32

q

Answer 32

frequency of recessive allele a