Genetics Chapter 6 Gene To Phenotype

Front 1

lethal alleles

Back 1

can cause death

Front 2

whats one way to keep lethal alles in the laboratory

Back 2

have them be temperature sensitive (ts) mutants

Front 3

ts mutants

Back 3

temperature sensitive mutants

Front 4

a ts mutant is ______________ at permissive temperature

Back 4

wild type

Front 5

a ts mutant is _______________ at the restrictive temperature

Back 5

mutant

Front 6

for coat color genes in mice. Why does the yellow coat show an inheritance pattern of 2:1 when 2 yellow mice are crossbred.

Back 6

you should get a ration of 1:2:1 but the any homozygous yellows die. and so the living mice are in the 2:1 ratio.

Front 7

For the yellow mice experiment when crossbreeding 2 yellow mice where would you see the proper 2:1 ratio

Back 7

if you looked at the zygotes

Front 8

sublethal alleles

Back 8

they reduce the viability of the organism but dont kill all of them.

Front 9

whats the effect of sublethal alles on progeny ratio

Back 9

skew them.. instead of getting 50% and 50% you might get 60% and 40%.

Front 10

pleiotropic effects

Back 10

single mutation in a gene having multiple effects

Front 11

whats the steps in for identyf genes that contr to a part biol property?

Back 11

1. treat with mutagens
2. test mutants to see how many gene loci are involved
3. combine mutat pairwise to form double mutants

Front 12

whats the steps in for identyf genes that contr to a part biol property? (summarize)

Back 12

1. hunt
2. tests for allelism
3. tests for gene interaction

Front 13

complementation

Back 13

production of wild type phenotype when 2 haploid genomes bearing diff recessive mutations are united in the same cell.

Front 14

if recessive mutations are alleles of the ____________________ they will not produce wild type progeny

Back 14

same gene

Front 15

for harebell plants (wild type blue)
what does w1/w1 X w2+/w2+ mean?

Back 15

the F1 indiv will have 2 defect alleles for w1 but enzyme 2 will be func.

Front 16

complementation is a ____________________ of the wild type alles of 2 or more genes

Back 16

cooperative interaction

Front 17

in a ____________________ the complementation test cant be performed by intercrossing

Back 17

haploid organism.

Front 18

heterokaryon

Back 18

fusion of 2 diff nuclei in one cell

ex: fungi

Front 19

why do you make a heterokaryon for a fungus

Back 19

to test for complementarity because its a haploid organism.

Front 20

f2 generation from the F1 dyhybrid F1 harebell plants has blue and white plants in a ration of 9:7. Why

Back 20

9:7 is really a variation of 9:3:3:1 but 3,3, and 1 have been combined

Front 21

Corn snakes
a snake that has o/o; b+/- will be?

Back 21

black because it lacks orange pigment

Front 22

corn snakes
F2 generation from F1 o+/o; b+/b has a ratio of 9:3:3:1. what does this prove?

Back 22

that the interacting genes are independent.

Front 23

epistasis

Back 23

ability of a mutation at one locus to override a mutation at another in a double mutant.

Front 24

epistatic

Back 24

the overiding mutation

Front 25

hypostatic

Back 25

the overidden mutation

Front 26

the epistatic mutation is of a gene that is ________________________ than that of the hypostatic

Back 26

farther upstream

Front 27

a phenotypic ratio of _____________________ is a mark of epistasis

Back 27

9:3:4

Front 28

epistais is inferred when a mutant allesle of one gene ____________________ of alleles of another gene ___________________ its own phenotype

Back 28

masks, expresses

Front 29

the double mutant w/w; m/m produces white flowers, showing that ____________ is epistatic to ______________.

Back 29

white is epistatic to magenta

Front 30

suppressor mutation

Back 30

mutant allele of one gene that reverses the effect of a mutation of another gene.

Front 31

What is the result of a suppressor mutation

Back 31

wild type phenotype

Front 32

coat color inheritance in labrador retreivers e/e prevents

Back 32

color deposition in hair

Front 33

revertant

Back 33

reversals of the original mutational event

Front 34

revertant a+ x standard wild type a+
what would the progeny be

Back 34

all a+

Front 35

yeast are
a. haploid
b. diploid

Back 35

a. haploid

Front 36

what are the signs of suppressor versus epistasis

Back 36

1. modified phenotypic ratio
2. only 2 phenotypes ( not 3 )

Front 37

if you see 3 phenotypes when dealing with supressors and espistatis what is it probably?

Back 37

epistasis

Front 38

one moleculary mechanism for supression is?

Back 38

that the first mutation changes the "Key" and the suppresor changes the "lock" so that it now fits the changed key.

Front 39

a suppressor mutation might undo a problem with ?

Back 39

protein- protein binding

Front 40

in protein protein binding a suppressor mutation might cause a _____________________ in the second protein

Back 40

compensatory shape change

Front 41

if a mutation causes a block in a metabolic pathway, the suppressor might?

Back 41

find a way of bypassing the blocked pathway

Front 42

some regulatory mutations of _______________________ of the target gene

Back 42

change the level

Front 43

a mutation in a regulatory protein can?

Back 43

downregulate or upregulate the transcribed protein

Front 44

What phenotypes indicates a modifier?

Back 44

appearance of 2 grades of mutant phenotypes within the "a" progeny.

Front 45

synthetic lethals

Back 45

is when 2 viable single mutants are intercrossed to become lethal.

Front 46

True or false
A cell has many duplicate or backup systems and pathways

Back 46

true

Front 47

a synthetic lethal can occur when you have mutations in?

Back 47

a system and in its "back up" system.

Front 48

penetrance

Back 48

percentage of individuals with a given allele who exhibit the phenotype associated with that allele.

Front 49

if you have a certain genotype, why might you not express it?

Back 49

1. infl of environm
2. infl of other genes
3. mutant effects might be too small to see or measure

Front 50

expressivity

Back 50

degree of which a given allele is expressed at the phenotypic level.

Front 51

expressivity measures the _____________________ of the phenotype

Back 51

intensity

Front 52

Give an example of expressivitiy

Back 52

"brown" animals from different stocks might show very different intensities of brown pigment from light to dark

Front 53

formula for chi square test is?

Back 53

Sum[O-E]^2/E for all classes