Human Population Genetics Flashcards
When did humans split from chimpanzees?
4-7 million years ago.
What is the “Out-of-Africa” theory?
The theory that archaic Homo in different places of the world was replaced by Homo sapiens from Africa (recent common origin).
What is the “Multiregional” theory?
The theory that archaic Homo in different places of the world evolved independently into Homo sapiens (ancient common origin).
How can DNA be used to generate a timeline?
A) Converting pairwise distance between 2 species sequences into a rate of change per year, using a well-dated fossil that lies at the base of 1 lineage.
B) Per-generation rates of sequence change can be inferred with sequence data across multi-generational pedigree.
C) DNA from well-dated fossil material can be used to calibrate a rate of sequence change.
When did Neanderthals diverge from Homo sapiens?
Around 500,000 years ago.
Do long shared haplotypes (between 2 lineages) tend to be recent or older?
Recent as haplotypes become fragmented over time.
Do short shared haplotypes (between 2 lineages) tend to be recent or older?
Older as these haplotypes have undergone fragmentation.
In Europeans and East Asians, what % of the genome is from Neanderthals?
On average 2%.
What is the function of the EPAS1 gene and what hominid did it originate in?
EPAS1 is a hypoxia pathway gene. It is very common in Tibetans and originates from Denisovans. EPAS1 is associated with differences in haemoglobin concentration at high altitude.
What is the genetic make-up of native Britons?
British genomes are 25% German and 45% French (Norman Conquests). The Romans and Vikings left little genetic traces.
What are some genetically based traits that evolved in the human lineage?
Hair that keeps growing. Eye colouration. The ability to digest milk after infancy. Highly articulate speech. Bigger brains.
Why do recessive alleles remain in the population despite being selected against?
Recessive alleles “hide” in heterozygotes.
How are Arctic populations adapted to a high fat diet?
A mutation in the CPT1A gene gives a metabolic advantage for dealing with a high fat diet. It is very common in Arctic populations - up to 90% of individuals.
What are the genetic consequences inbreeding?
Increased homozygosity.
Higher frequency of heritable recessive diseases.
Likelihood of pairing of recessive deleterious alleles.
What are the social consequences of inbreeding?
Concentration of wealth and power.
Reduction of ties with other groups.
