Pop Genetics

Front 1

gene pool

Back 1

all the alleles of every gene in a population

Front 2

population

Back 2

group of individuals of the same species that occupy the same region and can interbreed with one another

Front 3

polymorphism

Back 3

the prevalence of two or more phenotypic forms in a population
the phenomenon in which a gene exists in two or more alleles within a population

Front 4

allele frequencies

Back 4

number of copies of an allele in a pop/ total # of alleles for that gene in a pop

Front 5

genotype frequency

Back 5

# of indiv with a particular genotype in a pop/ tot # of indiv in a pop

Front 6

conditions of Hardy- Weinberg

Back 6

no new mutations, no genetic drift, no migration, no natural selection, random mating

Front 7

random genetic drift

Back 7

changes in allele frequencies in a population due to chance fluctuations. favors the loss of an allele of its fixation at 100%
depends on pop size
small pop- likelihood of fixation high

Front 8

probability of fixation

Back 8

1/2N

Front 9

expected number of new mutations

Back 9

2Nmu

Front 10

probability of elimination

Back 10

1- (1/2N)

Front 11

# of generations until fixation

Back 11

t=4N

Front 12

bottle neck effect

Back 12

type of genetic drift that occurs when most of the population is eliminated without regards to genetic composition

Front 13

founder effect

Back 13

changes in allele frequencies that occur when a small population separates from a larger population and establishes a colony in a new location

Front 14

gene flow

Back 14

individuals migrate between populations that have different allele frequencies, and the migrants breed successfully with the recipient population

Front 15

darwinian fitness

Back 15

the relative likelihood that a genotype will contribute to the gene pool of the next generation

Front 16

directional selection

Back 16

favors individuals at one extreme of a phenotypic distribution that are more likely to survive and reproduce in a particular environment

Front 17

stabilizing selection

Back 17

the extreme phenotypes for a trait are selected against, and those with the intermediate phenotypes have the highest fitness values
-decreases genetic diversity

Front 18

Disruptive selection

Back 18

favors the survival of two or more different genotypes that produce different phenotypes
-diverse environments

Front 19

balancing selection

Back 19

genetic polymorphisms
- a pattern of natural selection that favors the maintenance of two or more alleles
ex: heterozygote advantage and negative frequency dependent selection

Front 20

microevolution

Back 20

changes in a
population gene pool
from one generation to
the next

Front 21

haplotype

Back 21

a set of alleles that are closely linked and inherited as a group

Front 22

heteroplasmy

Back 22

variation in the genomic DNA of organelles (chloroplasts or mitochondria) within a cell

Front 23

cytogenetic mapping

Back 23

localizes genes to microscopically visible positions on a chromosome

Front 24

linkage mapping

Back 24

places genes on chromosomes according to the frequency of recombination btw different loci

Front 25

physical mapping

Back 25

identifies the position of genes within the sequenced DNA

Front 26

Fluorescent in situ hybridization (FISH)

Back 26

localization of genes to general region of particular chromosome

Front 27

simple translocation

Back 27

when a single piece of chromosome is attached to another chromosome

Front 28

reciprocal translocation

Back 28

when two different types of chromosomes exchange pieces - producing two abnormal chromosomes carrying translocations

Front 29

homologues

Back 29

genes derived from a single ancestral gene

Front 30

paralogues

Back 30

homolgous genes within a single species

Front 31

orthologues

Back 31

homologous genes found in different species

Front 32

pericentric inversion

Back 32

centromere lies within the inverted region of the chromosome
(duplicated/deleted)

Front 33

paracentric inversion

Back 33

centromere is found outside the inverted region
(acentric fragment & dicentric chromosome)

Front 34

inversion heterozygote

Back 34

carries one copy of a normal chr4omosome and one copy of an inverted chromosome

Front 35

dicentric chromosome

Back 35

two centromeres

Front 36

acentric fragment

Back 36

chromosome without any centromere

Front 37

robertsonian translocation

Back 37

two non-homologous acrocentric chromosomes are joined at breaks that occur near the centromere

Front 38

alternate segregation haploid cells

Back 38

two normal chromosomes, two reciprocal balanced translocations

Front 39

adjacent-1 segregation haploid cells

Back 39

4 unbalanced cells (one of each type of centromere)

Front 40

adjacent-2 segregation haploid cells

Back 40

4 cells unbalanced (both copies of the centromere on same chromosome into daughter cell)
requires incorrect segregation of the centromeres during meiosis I)

Front 41

euploid

Back 41

chromosome number is an exact multiple of a chromosome set

Front 42

polyploid

Back 42

chromosome number is a multiple greater than 3 of a chromosome set

Front 43

aneuploid

Back 43

not euploid; chromosome number is NOT an exact multiple chromosome set

Front 44

trisomy

Back 44

having 3 copies of a particular chromosome

Front 45

monosomy

Back 45

having 1 copy of a particular chromosome

Front 46

endopolyploidy

Back 46

occurrence of polyploid tissues in otherwise diploid organism

Front 47

polytene chromosomes

Back 47

repeated rounds of replication without cellular division

Front 48

mechanisms of aneuploidy

Back 48

meiotic nondisjunction, mitotic nondisjunction, alloploidy

Front 49

meiotic nondisjunction

Back 49

failure of correct chromosomal segregation in meiosis

Front 50

mitotic nondisjunction

Back 50

failure of correct chromosomal segregation in mitosis

Front 51

alloploidy

Back 51

having two or more sets of chromosomes from different species