Molecular Evolution (DNA/protein record in primate evolution) Flashcards
Homologs
similar genes across multiple species
Molecular Clock Hypothesis
genetic differences between two species is proportional to the time they diverged from common ancestor
HAR1 (human accelerated region 1)
DNA sequence found in all vertebrates: unchanged until human lineage, codes for RNA molecule: HAR1 plays a key role in brain cerebral cortex development
FOXP2
gene found in families affected by a speech disorder, regulates expression of several other genes: including several involved in development
Meiosis
Form of cell division that produces gametes, reduces # of chromosomes by half, full chromosome restored during fertilization: genetic variation –> chromosome/gene shuffling during meiosis
Chromosomal shuffling/Crossing over
genetic variation during meiosis
Point Mutations
single/few nucleotides, deletions/insertions/frame-shift mutations; nonsense (change to STOP), missense (different amino acid)
New Allele
same location, small change: does not increase amount of info in genome, new gene increases information/different location
Unequal crossing over
alignment during meiosis is imperfect, some cells lose or gain genes/exons
Transposition (jumping genes)
move around in genome, some make copies: some bring new functions to existing genes by inserting exons
Retroposition
Type of transposable element: reverse transcriptase makes DNA complementary (CDNA) to the mRNA –> inserted somewhere in genome/takes on new function
Transposases
enzymes that catalyze transposition
Mobilome
genetic elements that move/have moved around within genome/across genomes (transposons, plasmids, bacteriophages)
Horizontal Gene Transfer
mobile mechanism that contributes to spread of antibiotic resistance
