Organic evolution unit 5, 6, 8

Evolutionary Genetics

Gene

A segment of DNA whose nucleotide sequence is used to make a functional RNA or protein

gene expression

The process of synthesizing RNA or protein using the sequence of a gene; includes how much of the protein is made

Gene regulation

Mechanisms that control levels of gene expression—can block transcription, translation, or protein function

Mutation

Any change to the genomic DNA sequence of an organism; produced by replication errors and source of all heritable variation

Deleterious

A harmful mutation that lowers survival or reproduction.
most non-neutral mutations are deleterious

Allele

a version of a gene

genotype

combination of alleles an individual carries at a given gene

phenotype

observable traits resulting from genotype and the environment

population

A group of interacting individuals in a species

population genetics

Study of allele and genotype frequencies within a population, and how they change through time

Gene trees

Phylogenies of a single gene or allele showing how gene copies descend from earlier copies

Coalescence

Looking backwards in time, when two gene copies merge into a common ancestor, called a coalescent event

Why are DNA, RNA, and proteins important to evolution?

DNA holds heritable information; RNA carries it; proteins determine phenotype—variation here enables evolution.

Why are mutations critical?

They create all new alleles and all heritable variation.

Name ways mutations alter DNA.

Point mutations, insertions, deletions, frameshifts, duplications, inversions, chromosome fusion, genome duplication.

Expected effects of mutations on fitness?

Mostly neutral; non-neutral mostly deleterious; beneficial mutations rare but important.

How do you test Hardy Weinberg Equilibrium

Compare observed genotype frequencies to expected (p², 2pq, q²); significant deviation = evolution

How does coalescent theory show population growth?

Growing pops have slower coalescence, with more events near the root. Shrinking pops have faster coalescence and more events near tips.