Vocab From Test 1 Of Genetics

Front 1

Mendel's First Law

Back 1

Each trait is controlled by particular factors that occur in pairs. These pairs separate during gamete formation so that each gamete receives one pair of diploid chromosomes. The double number is restored upon fertilization.

Front 2

Test Cross

Back 2

Crossing to a pure breeding recessive organism

Front 3

Gene

Back 3

One of Mendel's "factors" that controlled the traits that he observed.

Front 4

Allele

Back 4

An alternate form of a gene (ie yellow and red)

Front 5

Gamete

Back 5

Sex cell, sperm and egg, or ovum and pollen.

Gametes carry only 1/2 the regular number of chromosomes. This number is restored upon fertilization.

Front 6

Zygote

Back 6

Formed by the fusion of two gametes.

Front 7

Homozygote

Back 7

A cell that carries identical alleles of a gene (ie AA)

Front 8

Heterzygote

Back 8

A cell that does not carry identical alleles of a gene.

Front 9

Mendel's Second Law

Back 9

Law of independent assortment:

Genes for different traits assort independently of one another. In other words, genes on different chromosomes behave independently in the production of gametes.

Front 10

How can you tell if two alleles are alleles of the same gene?

Back 10

They separate during gamete formation.

Front 11

When you see distorted Mendelian ratios, what should you expect?

Back 11

two or more genes are involved in determining the phenotype.

Front 12

Epistasis

Back 12

Masking the effect of one gene by the allele of another gene.

Front 13

Pleiotrophy

what is the disease associated with this word?

Back 13

pleiotrophy is the production of superficially (phenotypically) unreleated effects by a single allele.

Waardenburg's Syndrome: white furlock, deafness and different colored eyes.

Front 14

What did cuenot discover?

Back 14

It was impossible to get a pure breeding line of yellow rats because the YY genotype was lethal and the rats died in utero. This means that y is an essential gene, without this allele the rat dies.

Front 15

Penetrance

Back 15

The percentage of carriers that are affected in the same way.

Front 16

expressivity

Back 16

The degree to which phenotype is altered in those that are affected.

Front 17

probability

Back 17

Proportion of time an even is expected to occur in repeated trials.

Front 18

binomial formula

Back 18

P= n!/((s!)(t!)) (p)to the s times (q) to the t

Front 19

What is the cut off for the P value which says that our data does not fit the model well enough to keep it?

Back 19

5%

Front 20

what is chi squared?

Back 20

(observed - expected )squared all over expected.

Front 21

August Weismann

Back 21

he did experiments to see if physical changes were incorporated into our genetic material and passed on to the next generations. He cut off the tails of 22 generations of mice to see if the trait would become heritable. It did not.

Front 22

Interphase

Back 22

-phase between cell divisions
- chromosomes are elongated and difficult to see under light microscope
-stain cell --> see chromatin

Front 23

Prophase-

Back 23

condensation occurs until separate bodies called chromosomes are distinguishable.
-centrioles slowly move to opposite poles.
-spindle proteins slowly form
-nuclear envelope completely breaks down by the end of prophase

Front 24

Metaphase

Back 24

Spindle fibers line the chromosomes up on the metaphase plate .

-microtubules attach at the kinetochore, or region near the centromere of the homolog

Front 25

Anaphase

Back 25

Movement of chromosomes to opposite ends of the cell.

Front 26

what is a daughter chromosome?

Back 26

the name for each of the sister chromatids once they have separated and begun to migrate towards opposite poles.

Front 27

Telophase

Back 27

-daughter chromosomes assemble at the opposite end and elongate.
-nuclear envelope reforms and the spindle breaks down.
-nucleolus reforms.

Front 28

by looking at chromosomes we discovered?

Back 28

1. chromosomes occur in morphologically identical pairs

2. chromosome types are constant within a species and form a karyotype

Front 29

Describe prophase I of Meiosis I

Back 29

the cell forms a temporary 2n stage, when the homologs double and there are 2 centromeres. the sister homologs associate and a bivalent is formed. This is where crossing over occurs.

Front 30

chiasm

Back 30

the place where crossing over takes place.

Front 31

How are the products of meiosis II different from the products of mitosis

Back 31

- Mitosis produces a cell that has the same number of chromosomes as it started out with.

-There is not crossing over in mitosis

-meiosis creates 4 haploid gametes which are NOT identical to the original diploid cell because crossing over has allowed the genetic material to recombine and enhance gametic diversity.

Front 32

What did elanor carothers do?

Back 32

observed that a mutant strain of grasshoppers had a short variation of one chromosome

-she observed and accessory chromosome that assorted independently of the short variant of chromosome.

-

Front 33

Mclung

Back 33

-the accessory chromosome determines sex: grasshoppers have XX if female and X0 if male.

Front 34

Thomas Hunt Morgan

Back 34

He proposed that the gene for eye color of flies is located on the x chromosome.

also showed criss cross inheritance, sons look pheontypically like the mothers and daughters look phenotypically like their fathers.

Front 35

what is the condition of x linked genes in males called?

Back 35

Hemizygous

Front 36

What did Sutton propose?

Back 36

chromosome theory of inheritance: genes are on chromosomes.

Front 37

Calvin Bridges

Back 37

discovered that in about 1/2000 cases of drosophila, there was not a criss cross inheritance pattern.

The exceptional white eyed daughters were called matroclineous acceptions.

acceptional sons were patroclineous acceptions.

these rare mistakes were caused by non disjunction.

Front 38

define the wild type allele

Back 38

designated with a superscript plus.

it is the allele that is considered "normal"

Front 39

What is the difference between

w(plus)/w
and
W(plus)/W

Back 39

If the first letter of the gene symbol is lowercase, that means that the first variant found is recessive to the wild type(wplus is dominant)

If the gene symbol uppercase, then the first variant found is dominant to the wild type (W is dominant

Front 40

what determines sex in drosophila?

Back 40

number of x's. one x is a male, and xx is a female

Front 41

what sex is xxy in drosphila?

xo?

Back 41

xxy is female

xo is male.

Front 42

sex-linked

Back 42

located on a sex chromosome

Front 43

hemizygous

Back 43

x linked gene in a male. There is only one copy of the gene (one x) in a male genotype

Front 44

What did the moth study show?

Back 44

some species, like birds, butterflies and moths have females that are heterogametic (ZW) and males that are homogametic (ZZ

Front 45

what is XO in humans called?
What are the characteristics?

Back 45

Turner's syndrome

-underdeveloped sex characteristics

-webbed skin on neck

Front 46

xxy in humans

Back 46

kleinfelters

males, feminized, with mild breast development, sparse body hair, almost always sterile, mentally subnormal.

Front 47

XXX

Back 47

female
relatively normal
sometimes tall, with subnormal intelligence.

Front 48

What is the path the y gene takes to determine the sex?

Back 48

Y causes the gonads to become testis.

testis secrete androgens and testosterone that stimulate the rest of the embryo to become a male.

Front 49

what is the primary sex determination?

secondary?

tertiary?

Back 49

primary: sex of gonads

secondary: sex of genetalia (controlled by hormones)

tertiary: events at puberty.

Front 50

Describe the mutation that can occur with the Testicular Feminization Gene

Back 50

Tfm encodes androgen receptors that detect when the testis secrete androgens.

if there is a mutation in this gene, the androgen receptors don't function and the secondary and tertiary sex characteristics develop as female.

Front 51

How does Y determine gonad sex?

Back 51

the testis determining function TDF contains a gene called Sry which encodes a transcription factor of 204 amino acids. If sry region is inherited into XX, then they can be phenotypically female.

Front 52

consanguineous mating

Back 52

mating between related individuals

Front 53

What can you assume about pedigrees?

Back 53

assume allele has complete penetrance.

assume that if the trait is rare, individuals who marry into the family carry only normal alleles.

Front 54

How can a gene violate Mendel's second law?

Back 54

If they are close together on the same chromosome.

Front 55

cis

Back 55

alleles on the same homolog

Front 56

trans

Back 56

alleles on different homologs

Front 57

linkage

Back 57

association together of genes on the same chromosome

Front 58

recomgination

Back 58

process of generating new gametic types (non parental gametes)

Front 59

recombination frequency

Back 59

(nonparental gametes)/ total gametes

Front 60

why do different genes have different recombination frequencies?

Back 60

morgan said that it had to do with the distance appart of the genes.

Front 61

recombination frequency between any two genes is.........

Back 61

a constant and reproductable value that is always less than 50%

Front 62

What are the 4 stages of prophase I in Meiosis I

Back 62

Leptotene
Zygotene
Pachytene
Diplotene

Front 63

Leptotene

Back 63

first stage of prophase I

"thin thread stage", chromosome condensation is just beginning and appear as thin threads.

Front 64

zygotene

Back 64

second stage of Prophase I

condensation continues and you can see beadlike regions of localized condensation along the chromosome.

homologs become physically associated in this stage! (synapses form)

Front 65

chromomere

Back 65

bead like regions along the chromosomes that appear during zygotene. The chromomeres on sister homologs line up to form synapses.

Front 66

synapses

Back 66

intimate chromosome by chromosome pairing along their length. produces bivalence.

Front 67

Pachytene

Back 67

thick thread stage;

homologs are completely synapsed

Front 68

what is the synaptic complex made of?

Back 68

central element and lateral elements

Front 69

Diplotene

Back 69

fourth stage of prophase

two thread stage

you can see that each chromosome has two chromatids

homologs seem to try to repell on another

Front 70

What holds the homologs together in diplotene?

Back 70

a. chiasma

b. sister chromatids adhere

Front 71

what causes the sister homologs to separate in diplotene

Back 71

sister chromatid adhesion vanishes

Front 72

what is interference?

Back 72

interference is the inhibition of one cross over by others nearby

Front 73

what is the coefficient of coincidence?

Back 73

(observed number of doubles)/(expected number of doubles)

Front 74

How do you solve for interference?

Back 74

1-(coefficent of coincidence)

Front 75

When is interference complete?

Back 75

Within 10 map units

Front 76

crossing over takes place when how many cromatids are present?

Back 76

4 (after replication)

Front 77

what is

a. the name of baker's yeast
b. what is special about baker's yeast?

Back 77

a. saccharomyces cervisial

b. they grow and divide by mitosis in either the diploid or haploid phase.

Front 78

ascus

Back 78

The meiotic products of sarchomyces cervisiae incorporated in a common cell wall.

Front 79

ascospore

Back 79

a highly resistant thick cell wall that envelopes each individual of the 4 meiotic products of sarchomyces cervisiae.

Front 80

how can you stimulate sarchomyces cervisea to undero meiosis

Back 80

starve them

Front 81

what are the two mating types of yeast

Back 81

a and alpha

Front 82

a and alpha are what kinds of cells?

Back 82

haploid

Front 83

What are groups of 4 spores in an ascus called?

Back 83

tetrad

Front 84

polar bodies

Back 84

nuclear material that is discarded during oogenesis, leaving only one haploid product and three polar bodies that degenerate.

Front 85

If all spore types are parental, how many cross overs where there to produce that tetrad?

Back 85

none

Front 86

If two spore types are parental and two are non parental, how many cross overs where there to produce that tetrad?

Back 86

1

Front 87

If all 4 spores in a tetrad are non parental, how many cross over's where there?

Back 87

2

Front 88

what does the adenine 2 gene do?

Back 88

colors the yeast red to show that it carries the mutant gene.

Front 89

How should parental and non parental genes be related if they are not linked?

Back 89

they should equal

Front 90

how do you calculate recombination frequency?

Back 90

non parental/ parental (100)

Front 91

what is the maximum recombination frequency?
why is this so?

Back 91

50%, because all 4 double cross over types are equally frequent

Front 92

orange bread mold, ascomieces (incorporates miotic product into cell wall)

Back 92

neurospora crassa

Front 93

what is special about neurospora crassa?

Back 93

the products of meiosis undergo mitosis

Front 94

what is the shape of the ascus produced by neurospora crassa

Back 94

tubular

Front 95

1st degree segregation

Back 95

where there has been no crossover in the 4 strand stage of neurospora crassa. aaaa++++

Front 96

2nd degree segregation

Back 96

one cross over in the 4 strand stage of nerospora crassa. aa++aa++

Front 97

what is a polymorphism?

Back 97

the fact that about 1/1000 base pairs differ between homologs

Front 98

what are the two kinds of polymorphisms in gene mapping

Back 98

1. single nucleotide basepairs
2. insertion/deletion polymorphisms (Indels)

Front 99

How do you detect RFLP's

Back 99

southern blotting

Front 100

founder effect

Back 100

change in allele frequency due to founding of a population by a small number of people.

Front 101

what is glutamine encoded by?

Back 101

CAG

Front 102

anticipation

Back 102

Huntington's disease get's worse with every generation

Front 103

What is the relation between the number of glutamines and the severity of huntington's disease

Back 103

the more glutamines, the more severe the disease (earlier age of onset, etc).

Front 104

why do extra glutamines cause HD?

Back 104

polyglutamines are resistant to proteolysis and accumulate in the neurons, specifically the nucleus.

Front 105

Why do CAG repeats tend to grow over time?

Back 105

-displacement of 5' end of okasawki fragment during the CAG run.

-normally a flap endonuclease could remove it.

-except the flap can bend back on itself and form a hair pin, with the C's and g's bonding togeher.

-the hairpiin and the normal run of CAG's is replicated and grow with each replication.

Front 106

what did Holliday propose was a precise mechanism for crossing over?

Back 106

a. pairing molecules
b. single strand's are nicked
c. exchange of 3' ends
d. ligase

creates a holliday structure in which the point of exhange can move back and forth.