genetics

transcription

dna to mrna

translation

mrna to protein

chromosomes

in cell nucleus, contains dna

genome

the sum of all genetic material in one complete set of chromosomes

autosomes

non-sex chromosomes

cell cycle

G2, S, G2, M

G1

growth, normal metabolic roles

S phase

replication

G2

growth and prep for mitosis

M phase

mitosis and cell division

meiosis

production of gametes, ends in haploid cells

A

promoter

B

exon

C

intron

locus

site/location on chromosome

gene

functional region at locus

alleles

different versions of a gene

how many alleles can be at a locus

2

genotype

genetic makeup of an individual

phenotype

observable trait on an organism, result of genetics, environment, and interaction btwn genes and environment

processes causing re-shuffling of genes

random migration of chromosomes, crossing over during meiosis

principle of segregation

each gamete will have one allele at any given locus

principle of independent assortment

different allele pairs segregate independently of one another

dominance

action of recessive completely masked by dominant, heterozygote has same phenotype as homozygous dominant

co-dominance

effect of both alleles observed, phenotype of heterozygote different to both homozygotes

incomplete dominance

phenotype of heterozygote is midway btwn phenotype of homozygote

epistasis

interaction of genes at different loci, when phenotype of one gene depends on or is modified by other genes

modifiers

other genes modify but don’t mask a phenotype, agouti locus controls distribution of pigment, dilution genes,

how many alleles can a population have at a locus

more than 2

allele frequency

proportion of different alleles within a population

polymorphic locus

if allele frequency is less than 0.95

factors affecting allele frequencies

population size, natural selection, migration, mutation

hardy-weinberg equilibrium

p² + 2pq + q² = 1

hardy-weinberg equilibrium assumptions

mating is random, allele frequencies are same in males and females, no natural selection, no mutation, no migration, population is large enough for no change in allele frequency btwn generations

exceptions to mendel’s rules

linked genes, mitochondrial genes, epigenetics, genes on sex chromosomes

genetic drift

when allele frequency changes over time, more effective in small populations

qualitative trait

set phenotype, measured descriptively, controlled by one gene

quantitative trait

distribution of phenotypes, measured numerically, controlled by many genes

additive variance

genetic factors that can be predictably transmitted to next generation, breeding value

non-additive variance

gene combinations unique to individual

heritability

proportion of observed variability in traits genetic in nature, capacity to pass on genes

selection differential

superiority/inferiority of selected animals compared to herd average