Key words and Hardy Weinberg

Gene

A sequence of DNA bases that codes for polypeptides

Allele

An alternate form of a gene

Genotype

the genetic make up of an organism

Phenotype

The observable characteristics that result from the genotype and environment

Homozygous

Same alleles

Heterozygous

Different alleles

Which is Homozygous?

DD

Which is heterozygous?

Dd

What is an example of a Genotype?

DD, Dd, dd

Test cross

Genetic cross used to determine the genotype of an organism expressing the dominant phenotype

Humans are diploid organisms. What does this mean?

2 copies of each chromosome

Locus

Allele of a gene is found at a fixed position

Haploid

Only one allele for each gene

Monohybrid cross

Likelihood of the different alleles of that gene being inherited by offspring of certain parents

Autosome

Chromosome that isn’t a sex chromosome but is linked

Species

A group of similar organisms that can reproduce to give fertile offspring

Population

Group of organisms of the same species living in a particular area at a time who can interbreed

Gene pool

Complete range of alleles present in a population

Allele frequency

How often an allele occurs in a population

What is the Hardy-Weinberg model?

Predicts that the frequencies of alleles in a population won’t change from one generation to the next

The Hardy-Weinberg is only true if we assume..

It’s a large population with no migration, mutations or natural selection and has random mating.

Equation for allele frequency

p+q=1

Equation for genotype frequency

p2+2pq+q2=1

p

Dominant allele

q

Recessive allele

p2

Homozygous dominant genotype

q2

Homozygous recessive genotype

2pq

Heterozygous genotype