2+3 Non-disjunction and ploidy + Gene Interaction

Question 1

what is mendels first law

Answer 1

Alleles of a single gene segregate independently from each other

Question 2

what is mendelas second law

Answer 2

Alleles of different genes segregate independently from each other

Question 3

If a male is affected by an X-linked trait, then all his daughters are ______ and all his sons ______

Answer 3

-carriers
- will not be affected (father doesn’t give son his X chromo)

Question 4

TF Nearly all affected people are male

Answer 4

T

Question 5

If a female is a carrier of an X-likned trait then ___ of her sons are affected and _____ her daughters are carriers

Answer 5

-half
-half

Question 6

for dominant x-linked diseases, Affected males transmit their trait to all the _______ and none of their _____

Answer 6

-daughters
-sons

Question 7

TF x-linked affected heterozygous females transmit the trait to all of their children regardless of sex

Answer 7

F, transmit to 1/2 their children

Question 8

what is an allopolyploid

Answer 8

the containment of the multiple copies of chromosomes of different species.

Question 9

what is an aneuploid

Answer 9

having mismatched number of chromos

Question 10

what is an autopolyploid

Answer 10

the containment of multiple copies of chromosomes in the same parent.

Question 11

what is an autosome

Answer 11

any chromosome that is not a sex chromosome.

Question 12

what is a chromatid

Answer 12

One of the two daughter strands of a duplicated chromosome

Question 13

what is a chromosome

Answer 13

2 sister chromatids

Question 14

what is a diploid

Answer 14

2n - normal for most eukaryotes

Question 15

what is euploidy

Answer 15

having a normal number of each chromosome

Question 16

What is polyploidy

Answer 16

extra copies of each chromosome
- triploid = 3n
- tetraploid = 4n

Question 17

what is a haploid

Answer 17

missing copies of all chromosomes ( only 1 set of chromos)
- monoplod = 1n

Question 18

what does hemizygous mean

Answer 18

they have only one copy of it present in their organism. For example, in mammals, males are hemizygous for genes on the Y chromo

Question 19

what is a karyotype

Answer 19

the number and visual appearance of the chromosomes in the cell nuclei of an organism or species.

Question 20

what is monosomy

Answer 20

Imbalance in chromosome
Monosomy is an example of aneuploidy, which is an imbalance in chromosome numbers.

Question 21

what is nondisjunction

Answer 21

the failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes

Question 22

what are intra-allelic effects

Answer 22

○ Multiple alleles of the same gene affecting the phenotype together

Question 23

what does haplosufficent mean

Answer 23

More formal form to say dominance
○ Only requires one copy for its phenotype to be produced

Question 24

what does haploinsufficent mean

Answer 24

○ Formal way to say recessive
○ Genes that require more than 1 copy to produce the phenotype

Question 25

what is incomplete dominance

Answer 25

blended phenotypes ○ Heterozygote has a third phenotype - New phenotype not presented in parents ○ Third phenotype is a blending of the first 2

Question 26

what is codominance

Answer 26

Shared dominance ○ Not a blend but a 50/50 of the first 2 phenotypes ○ Ex) the A B O blood group

Question 27

what is a null allele

Answer 27

a nonfunctioning allele

Question 28

what is a hypomorphic allele

Answer 28

has partial function

Question 29

what is pleiotropy

Answer 29

Single alleles has more than 1 phenotypic effect

Question 30

A 2:1 ratio in a punett square indicates a _______ copy

Answer 30

lethal

Question 31

what is variable penetrance

Answer 31

Same mutant genotype may or may not show the phenotype (all or nothing)

Question 32

- What determines penetrance (if the phenotype is shown)

Answer 32

○ Modifier genes ○ Environmental factors ○ Allelic variation

Question 33

what is variable expressivity

Answer 33

all or some

Question 34

what is variable penetrance and expressivity

Answer 34

all, some, or none

Question 35

what are interallelic effects

Answer 35

○ multiple genes affecting the same phenotype

Question 36

what is a monogenic trait

Answer 36

1 gene accounts for 1 phenotype

Question 37

what is a pleiotropic gene

Answer 37

1 gene has multiple effects (phenotypes)

Question 38

what is a polygenic trait

Answer 38

multiple genes coding for 1 phenotype

Question 39

how can we test for a monogenic vs polygenic trait

Answer 39

compliment test

Question 40

what does a compliment test do

Answer 40

hide the mutations and find the WT phenotype

Question 41

how do we do a compliment test

Answer 41

cross homozygous recessive mutants

Question 42

in a compliment test, if both alleles of 1 gene are still mutant and have the recessive mutant phenotype, that means that

Answer 42

the mutations are on the same gene

Question 43

in a compliment test, if 1 allele of a gene is WT and have the WT phenotype, that means that

Answer 43

mutations are on different genes

Question 44

what is complimentary gene interaction

Answer 44

- compliment test - 2 loci, 1 trait, 2 phenotypes ○ Will get genotypic ration 9;7 (9; 3+3+1) after crossing F2 generation (white and blue flowers)

Question 45

what is additive gene action

Answer 45

○ 2 loci, 1 trait, 4 phenotypes - Alleles of 2 genes generate 4 phenotypes (orange and black snake)

Question 46

is additive gene action mendelian ? why ?

Answer 46

not mendelian 4 phenotypes for 1 trait

Question 47

what is duplicate gene action

Answer 47

○ 2 loci, 1 trait, 2 phenotypes ○ Ratio of dominant phenotype is many more than the recessive Only way to get the recessive phenotype is is both genes are double recessive (no dominance presence will give a recessive phenotype)

Question 48

what is epistasis

Answer 48

○ Allele of one gene overrides the other gene in the phenotype - If one gene is present the other gene is ignored and sits under the first gene

Question 49

what is dominant epistasis

Answer 49

- Dominant allele of 1 gene masks the effect of the second one (dominant or recessive) - 2 loci, 1 trait, 3 phenotypes - 12:3:1 phenotypic ratio (think of eggplants)

Question 50

what is recessive epistasis

Answer 50

- Recessive allele of 1 gene masks the effect of the second one (dominant or recessive) - 2 loci, 1 trait, 3 phenotypes - Phenotypic ratio : 9;3;4 (think of the labradoodles)

Question 51

give the phenotypic ratios for the following gene interactions - additive - complimentary - recessive epistasis - dominant epistasis - duplicate

Answer 51

9:3:3:1 9:7 9:3:4 12:3:1 15:1

Question 52

if we have 1 gene and the ratio is 3:1 it is ____ 1:2:1 is ____ 2:1 is ___

Answer 52

- Mendelian - Co-dominance - Lethal

Question 53

what is a hypostatic gene

Answer 53

one whose phenotype is altered by the expression of an allele at a separate locus, in an epistasis event. Example: aa bb In labrador retrievers