Genetic Variation Flashcards
Phylogenetic Tree
show evolutionary distance between species and even within species
Reasons the Mouse is a Good Model for Human Studies
~40% of genome is perfectly aligned, ~80% of mouse genes have a single human counterpart, mutation rat is twice as high in mouse genome
ortholog
gene differs in sequence but its main function is conserved across species
homolog
protein sequence identical
Outgroup
the least related to the other species in a phylogenetic tree (think wolves in a dog breeds tree)
How much of the genetic sequence is shared between humans and chimpanzees?
99.8%
What three factors resulted in humans and chimps being different?
- Protein evolution (small (0.2%), critical changes)
- Gene regulation
- Less is more
Does a species become more or less genetically diverse over time?
MORE genetically diverse (assuming random mating and stable population)
Bottleneck
a way to reduce genetic diversity (for example, creating breeds) (eliminates some alleles in some breeds)
Is there more genetic diversity within a breed or between breeds?
BETWEEN breeds
How can you reintroduce genetic diversity to a population?
cross-breeding
Comparing Humans?
can be done at individual or population level; 1 million variants are unique to each population, but still shared within the population
How many base pairs in the human genome?
~3 billion
Recombination vs Mutation
Recombination is a result of variability that is ALREADY PRESENT in the population.
Mutations introduce NEW VARIABILITY to the population.
Types of Variants/Mutations (3)
- Sequence Variants
- Structural Variants
- Chromosomal Abnomalities
Trisomy 21
extra chromosome 21, results in Down’s Syndrome
Chromosomal Fusion
part of one chromosome ran away from home to join another chromosome
Reciprocal Translocation
“The Holiday” - two chromatids swapped homes
Single Nuclotide Polymorphism (SNPs), aka point mutation
single base pair change