CH13: genetics

Gregor Mendel

an austrian monk who bred pea plants. accidentally provided evidence as to how inheritance worked. Father of modern genetics.

pea plants

self fertilizing plants with male and female parts

male plant parts

anthers with pollen

female plant parts

carpels

Mendel's Experiment

manually pollinate the pea plants and collect the seeds. record traits of the resulting offspring

hereditary units

genes. results of Mendel's experiment

homozygous alleles

same allele on both chromosomes. breeding true

breeding true

trait is 100% passed down

heterozygous alleles

different allele between both chromosomes. passing down depends on whether trait is dominant or not

genotype

genes and alleles. gives rise to phenotypes

phenotype

observable traits (visible)

dominant alleles

Masks the effects of other alleles, only in heterozygous individuals

recessive alleles

Allele that’s often masked by a dominant allele in heterozygous and homozygous individuals.

Mendel's law of segregation

in diploid cells there are two copies of genes that can have different alleles. during reproduction each parent randomly donates one of those genes/alleles

punnett squares

Diagram used to predict genotype and phenotype

codominance

two dominant alleles. Often see a mix of the two traits

incomplete dominance

when both alleles aren’t fully dominant or recessive. Often get a mix ( combination) of the two traits.

phenotypic plasticity

genotypes producing different phenotypes in response to environmental stimuli