genetics and inheritance

Question 1

genotype

Answer 1

all the genetic makeup of the organism

Question 2

genepool

Answer 2

ll the alleles within an interbreeding population

Question 3

population

Answer 3

all the individuals of the same species that occupy the same area

Question 4

phenotype

Answer 4

expression of its genetic constitution and its interaction with the environment

Question 5

alleles

Answer 5

different versions of the same gene

Question 6

locus

Answer 6

position of allele on the homologous chromosomes

Question 7

homozygous

Answer 7

two copies of a gene

Question 8

heterozygous

Answer 8

two copies of gene are different alleles

Question 9

co-dominant alleles

Answer 9

equally expressed in the phenotype

Question 10

gene pool definition

Answer 10

all of the alleles of all the genes of all the individuals in a population at a given time

Question 11

allelic frequency

Answer 11

The number of times an allele occurs within a gene pool

Question 12

Hardy-Weinberg principle predicts that:

Answer 12

the allelic frequencies from one generation to the next will remain constant

Question 13

factors affecting the Hardy-Weinberg principle

Answer 13

-no migration
-no gene mutation
-no selection for a particular allele

-large population
-random mating

Question 14

Hardy-Weinberg equations

Answer 14

P + q = 1.0

P2 + 2Pq + q2 = 1.0

Question 15

monohybrid inheritance meaning

Answer 15

inheritance of a single gene which determines a single characteristic

Question 16

monohybrid inheritance -Codominance

Answer 16

do not show a standard dominant/recessive relationship
superscript letters are used for the allele

Question 17

monohybrid inheritance - multiple alleles

Answer 17

several genes in a population
dominance hierarchy

Question 18

There was 850 fruit flies in a population.
510 fruit flies had the genotype W(H)W(N)
255 fruit flies had the genotype W(N)W(V)
85 fruit flies had the genotype W(V)W(V)
CALCULATE ALLELE FREQUENCY OF ALLELE W(V)

Answer 18

1700 alleles in frequency
2x85=170
1x255=255
255+170=425
424/1700
0.25

Question 19

950 flies in population
frequency of W(V) allele. was 0.2
calculate the number of expected individuals with the genotype W(N)W(V)

Answer 19

2X0.2X0.8=0.32
0.32X950=
304

Question 20

dominant characteristics rules

Answer 20

1. affected offspring must have at least one affected parent
2. unaffected parents only have unaffected offspring
3. if both parents are affected but child is unaffected, both parents must be heterozygous

Question 21

recessive characteristics

Answer 21

unaffected parents can have an affected offspring

Question 22

sex linked characteristics

Answer 22

controlled by genes located on one of sex chromosomes

Question 23

what are the male chromosomes

Answer 23

XY

Question 24

what are the female characteristics

Answer 24

XX

Question 25

why do men have more genetic diseases

Answer 25

For sex-linked genes, a female would have to have two copies of a recessive allele for it to appear in the phenotype, whereas males only need one.

Question 26

sex-link rules for recessive allele

Answer 26

-dads and daughters
daughter is affected
father is not affected
is recessive disease
so not sex-linked

Question 27

Dihybrid inheritance definition

Answer 27

a phenotype is inherited as a result of two different genes, thus two characteristics

Question 28

what is the ratio of dihybrid inheritence between homozygous parents?

Answer 28

9:3:3:1

Question 29

Autosomal linkage

Answer 29

chromosomes that are not directly involved in determining the sex of an organism.

Question 30

Crossing over process

Answer 30

Non sister chromatids on homologous pairs cross over to form a bivalent
Then forms a chiasma
Exchange of alleles to produce random recombinant offspring which display new combination of alleles

Question 31

Linkage group definition

Answer 31

Set of genes on the same chromosomes which tend to be inherited together

Question 32

What happens to the expected ratio when two genes are autosomal linked

Answer 32

Does not follow the expected phenotypic ratio

Question 33

What happens when genes are autosomal linked

Answer 33

Don’t follow the expected phenotypic ratio

Question 34

sex-linkage males vs females

Answer 34

female needs two copies of a recessive allele for it to appear in the phenotype, whereas males only need one

Question 35

sex link rules - how to look if it is not sex-linked

Answer 35

-if daughter is affected, father is not (recessive)
-if son is affected, mother is not affected (domindant)

Question 36

epistasis definition

Answer 36

interaction between two genes where one allele influences the expression of another