Unit 2 : Genetics, Inheritance, and Evolution

BIOL 1003

DNA

-made of nucleotides, double stranded

-in nucleus

-transcribed into RNA

gene

-a section on one strand of nucleotides

-in/on DNA

-transcribed into RNA

chromosome

-two strands of nucleotides, wrapped around proteins

-in cytoplasm

-passed from parent to offspring in meosis

nucleotide

link together to form the macromolecule in DNA or RNA

gene expression

process of going from DNA to RNA to protein

coding DNA strand to RNA 

A → U

T → A

G → C

C → G

mitosis

meiosis 1

meiosis 2

sex

gamete size

anisogamy

when gametes exhibit a different size (female = large gamete / male = small gamete)

isogamy

when gametes are the same size

hermaphrodite

individual who produces both egg and sperm

cell cycle

series of events that take place in a cell as it grows and divides

sister chromatids

replicated, identical, result in a copy of DNA

must be same length and are the same alleles

homologous chromosomes

2 chromosomes that have the same GENES

must be the same length, can have different alleles

heterozygous

two different alleles for a specific gene (Aa)

homozygous

the same alleles for a specific gene (AA or aa)

ploidy

number of sets of a chromosome in a cell

haploid = 1 set / diploid = 2 sets

ways that sexual reproduction creates new alleles

• crossing over

• independent assortment

• random fusion of gametes

independent assortment

the long chromosome pairs line up independent of how the short chromosome pairs line up (left and right)

during metaphase 1

mutation

error in replication

during interphase

crossing over

exchange genetic information between chromosome from sperm and chromosome from egg

during prophase 1

dominant

one chromosome must be present, masks recessive gene

recessive

two chromosomes must be present

co dominant

both phenotypes are fully expressed

incomplete dominant

there is no clear dominant allele, a different phenotype is expressed, “in between” phenotype

two fold cost of sex

1. cost of producing males → males cannot birth offspring

2. cost of passing on fewer genes → only 50% of genes (from each parent are passed down)

additional costs of sex

• cost of finding a mate → time, energy

• cost of infection → STD

muller’s ratchet

an explanation for why asexual reproduction can result in offspring that are less fit than their parent

sexual reproduction

producing offspring that are genetically different from yourself

deleterious alleles

harmful alleles that make an organism less fit

asexual reproduction

producing offspring that are genetically identical to yourself; clone

parasite or pathogen

organisms (or viruses) that harm other organisms

red queen hypothesis

an explanation for why sexual reproduction may be more adaptive than asexual reproduction; sexual reproduction speeds up evolution by creating more variation

coevolution

an arms race between pathogens and their hosts in which the host evolves to be resistant to the pathogen, and then the pathogen evolves to be able to infect the host, and so on

inbreeding

mating between closely related individuals

p value

a statistical measure used to determine the likelihood that an observed outcome is the result of chance (rather than the actual effect you are studying)

p < 0.05

reject the null (alternative hypothesis is supported)

p > 0.05

fail to reject the null (null hypothesis is supported)

disassortative

mating with mates who are different from yourself

cryptic female choice

when females control a male’s mating success by “deciding” whether or not to use the male’s sperm to fertilize her eggs, after they’ve already mated

bet hedging

spread risk across multiple options (offspring of multiple phenotypes) in order to increase the chances of survival and reproductive success of offspring