Genetics, Human Pop

Front 1

What is a genotype?

Back 1

combination of allele present in an individual
eg. BB/Bb.

Front 2

What is a phenotype?

Back 2

physical manifestation of a genotype

Front 3

What is an allele?

Back 3

Alternate form of a gene at a particular locus.

Front 4

What is a locus?

Back 4

actual location of an allele on a particular chromosome.

Front 5

What is a polymorphic loci?

Back 5

Chromosome site which have more than 1 allele for a given trait. Most loci are polymorphic in humans.

Front 6

Who is gregor mendel?

Back 6

1822-1884- inheritance of discrete traits follows particular laws.

Front 7

What is the law of segregation?

Back 7

During gamete formation, gene copies will separate so a gamete recieves only one copy.

Front 8

What is the law of independent assortment?

Back 8

alleles of different genes assort independently of one anther during gamete production.

Front 9

What is nuclear DNA (nDNA)

Back 9

3200 Mbp, 2 copies per diploid cell, 46 linear chromosomes per diploid cell.

Front 10

What is Mitochondrial DNA ?

Back 10

16569 Mbp, 2-10 copies per mitochondirion, 1000s of copies per cell, circular molecule

Front 11

What is a Homologous Chromosome?

Back 11

Chromosomes of same structure, 22 pairs of autosomes and 1 pair of sex chromosomes (xx-fem. xy-m) possesing genes for same trait at corresponding loci

Front 12

What is mitosis?

Back 12

Cell division where chromosome number is conserved. Diploid to diploid
4 phases involved

Front 13

What is Meiosis?

Back 13

Chromosome number halved. Diploid - Haploid. Results in the formation of gametes. "cross over" 8 phases involved

Front 14

What is a homozygote?

Back 14

two copies of the same alleles of a given gene

Front 15

What is the definition of heterozygote?

Back 15

Having two different alleles of a given gene.

Front 16

What is codominance?

Back 16

Two alleles having equal effect on phenotype trait
EG.
AB blood group

Front 17

What is incomplete dominance?

Back 17

two alleles are expressed creating an intermediate phenotype. eg. red and white resulting in pink flowers

Front 18

What are amino acids?

Back 18

building blocks of protein, created by DNA by transcription and translation.

Front 19

What is transcription?

Back 19

Process of creating a strand of RNA from DNA.

Front 20

What is translation?

Back 20

Process of creating protein through decoding the RNA.

Front 21

How does the immune system function?

Back 21

By recognizing and eliminating 'non self'

Front 22

What are leukocytes?

Back 22

White blood cells

Front 23

What are phagocytes?

Back 23

involved in 'non specific' cellular immune response.

Front 24

What are lymphocytes?

Back 24

involved in ' specific ' hormonal immune response

Front 25

What blood group is the universal receiver?

Back 25

AB
-With A and B surface antigens

Front 26

What blood group is the universal donor?

Back 26

O-
universal donor lacking surface antigens.

Front 27

What is private polymorphism?

Back 27

allele present in only one population.
eg. Diego group

Front 28

What is Tay- Sachs?

Back 28

Excessive accumulation' of fatty substances called ganglioside(GM2)

Front 29

What is PKU?

Back 29

accumulation of toxic amino acid phenylalalanine as infant.

Front 30

What is cystic fibrosis?

Back 30

disorder of exocrine glands.

Front 31

What is sickle cell?

Back 31

change in amino acid at one critical position on beta chain.

Front 32

Why might natural selection be responsible for the frequency of these diseases? (tay sachs etc.)

Back 32

Because it can't be:
- mutation- because it is a random process that foes not explain the concentration of tay sachs in askenazim
-gene flow- as it fails to explain why tay sachs deaths haven't eliminated the gene.
-genetic drift- although studies of mass patients traced it back to its ancestors, two other diseases caused by substances similar to GM2 in ashkenazim

Front 33

Natural selection( to explain the diseases as adaptation)

Back 33

-tay sachs common in ashkenazim, who were forbidden to own land and forced to work in crowded urban ghettos of east-europe in early 20th century, a time where 'tuburculosis' was prevalent, however, almost no tay -sachs patient had parents/grandparents who died of it. Studies show Tay-Sachs is an appropriate adaptation.

Front 34

Hardy Weinberg equilibrium

Back 34

- measure of micro-evolution or allele frequency= p^2 +2pq+q^2 = 1

Front 35

genotype frequencies

Back 35

relative proportions of different genotypes in a population

Front 36

Allele frequencies

Back 36

relative proportions of different alleles in a population

Front 37

Gene pool

Back 37

The totality of all allele frequencies in the population

Front 38

Evolution

Back 38

A change in allele frequencies over time

Front 39

H-W equilibrium is violated by ..

Back 39

Gene flow: movement of allele in and out of a population
Mutation: new alleles introduced into the population
Selection: difference in fertility/mortality of genotypes
Genetic drift: large populations so no errors are introduced by sampling

Front 40

Modes of natural selection

Back 40

-stabalizing
-disruptive
-directional
-sexual

Front 41

Stabilizing

Back 41

against both extremes of a trait range
i.e. individuals with extremely high or low values of a trait are less likely to survive and reproduce- human birth weights
-favors mean phenotype

Front 42

Disruptive selection

Back 42

Selection favoring two different phenotypes

Front 43

directional selection

Back 43

selection favoring one phenotype over the other

Front 44

sexual selection

Back 44

differential fertility based on the preferential selection of one mate type over another
Runaway sexual sel. eg.
-peacocks feathers

Front 45

Genetic drift affected by:

Back 45

-pop size
-num. of individuals sampled to make up the next generation (sampling error)

Front 46

admixture

Back 46

the process of gene flow b/w two or more initially different groups. eg. africans brought to the us against their will, europeans and africans genes mixed. (mainly through slave women bearing their masters children)

Front 47

Non-random mating

Back 47

It is not an evolutionary force.
Eg.- it cannot change allele frequencies over time (evolution) but non random mating makes it impossible to predict genotype frequencies from allele frequencies. Patterns here can influence rate of allele frequency change(evolution) by interacting with other evoltionary forces.