Genetic Drift, Natural Selection, & Immigration

Genetic Drift

This is evolution due to chance events in small populations with no external force.

Founder Events

New populations are often founded by a small number of individuals; almost always have changes in gene frequency.

Migration

This is leaving a population.

Emigration

This is coming into (joining) a population.

Linked Genes

Genes that are close together on a chromosome; tend to be inherited as a unit.

Linkage Disequilibrium

The non-random association of alleles on different loci.

linked

All mitochondrial genes are ____________.

Selection Sweep

When fixation at one locus leads to fixation at other loci that are linked to it. When a favorable allele passes on, any other alleles **linked** to it also pass on (even if they’re not beneficial).

Codon

A triplet set of nucleotides that code for a specific amino acid (start/stop).

Exons

DNA sequences that are part of mRNAs.

Introns

DNA sequences that disrupt encoded proteins and RNAs & must be edited out.

introns

There are no ___________ in bacteria or mitochondrial DNA.

Splicing

This process removes the introns (gets rid of junk DNA).

Promoters

DNA sequence that tells polymerase where to set down to begin transcription

Regulatory Elements

These cause more or less transcription of a gene.

Junk DNA

This is DNA that serves no known purpose.