L6 population specific variation Flashcards Preview

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Flashcards in L6 population specific variation Deck (39):

how does genetic diversity arise in populations

variants intro by muts
lost by genetic drift


what the relationship between diversity and age of population

older pop more genetic diversity


whatcan be revealed from the genetic diversity of a population

split from ca
slection pressures within the envuroment


hwo does geogrpahy link to genetic diversity

diversity varies around globe
some phy barriers explan diversity
norm in same area have same ptype


what gene used as a measure of genetic diversity

cd4 - a glyco pr on immune cells
high in afr
low rest of world


name some of the large scale sequencing studies

1000 genomes project
UK10k project


what the findings of the 1000 genomes project

looked at genomes from 26 pops
found 88 mil variants
afr had most variants show older pops
when look at variants that are common in pops but rare globally most div in afr and some peruvian tribees
finaland also higher div than rest eu


what are the gentic impacts of colonisation and migration

founder effect
gene flow


what is admixture

the creation of hybrid pop from two ancestral pop


what the general genetic consequence of admixture

introduce new variants
results in incr variation in qtl traits
diff rec alleles decr disease


what other consequence of admixture

new pathogen exposure incr disease


what did genetic studies show about disease outbreaks in mexico in 16th C

salmonella outbreak
strain had been in eu 300 yrs before
spanish conquest - poor sanitary conditions


when did the movement into the american occur



what have studies found for genetic evidence of the migration into n.am

studied ams. siberians no eu admix
n.am stem from one group split with asians 23,000
spent 8000 bering strat
entered n.am in a single waave


whta have studies shown about the n.am and s.am split

found ev of aus melanesia in dna of s.am (Raghavan et al., 2015)


what have gentic studies shown about n.am and inuit population

seperate clade whihc are closer to indigenous siberians


what have genetic studies shown about the oceana and s.am populations

found amazonians share more sim with present day aus melanesians (1-2% ancestry)


what is population y

an ancestral population beleived to have contributed to both s.am and oceana


who is pop y thought to be most related to in present day pop and what this evidenve of

than e. asain/siberian
no admixture in bering strait


what problem with conclusions from pop y at the moment

no ancient dna prove
although craniomorphological features of ancestral fossils support


when and where fossil usr1 from

beringia alaska
dated 11.5kya


what has fossil usr1 revelaled/suggested

genome seq shown more related to n.am than any other modern pop
is equal rel to all n n.am and s n.am = usr1split with ancestor of them 20-9kya
(nnam and snam then split at 15kya)
has no pop y ancestry
usr1 decendents in beringia until 11.5
usr1 ancestor split with e.asians 36kya but genome persit until 26kya
also show that after 11.5kya some nna have gene flow from siberian pop


what have studies of south american population revealed about migrations into the countries

varied by countries


what country has the highest n.am genetic sim

n. am


what country has the smallest afr contribution



where has most the admix in the s.am pops come fromq

eu -iberia = spain


what findings for argentina migration / genetic input

highest number of cluster from italy, models show the migr between 3-9 gen ago. fits wiht the migr that occured in the 19thC-20th C
equal contribution from clusters eu/afr and native american


what findings for ecuador migration / genetic input

the least eu/afr input


what have studies in south american native american shown

no evidence of northern native american in latin derived s.am
there are two clusters
-central andean
-other souther native american
= andes geog barrier


what have genetic studies looking at sex xhr in south america shown

gender disparity
more x linked native american allele compared to autosomes
reflects that mainly eu men came over in migr


what is the finnish disease spectrum

different profile of recessive inherited diseases that the finnish pop have compared to surrounding pops
40 rare disease
20% carriers
1:1500 affected


what cause the finnish disease spectrum

geog and language barrier


what different about y chr in finnish pop

diversity lower than other eu pops


give an example of a disease of the finnish disease spectrum

,eckel syndrom
auto rec
cyctic kidney
worlwide incidence 0.2 per 1000
finalnd 1.1 per 1000


what examples of environmental adpatation in gentic diversity

inuit and diet (FADS1-3)
lactose tolerence eu and e.afr (MCM6)
light skin eu (MATP/TYR)
altitude andes and himalayans (EGLN1)


describe the fidings of enviromental adaptation in inuit pop

evidene for positive sel in 5 genes
inc FAD1-3
FADS1 and " encode enzymem that convert PUFA into biol active forms
also strong adpatation signatiures for height and weight
suggest adaptation to survive on diet with no neg impact onw weight


what is the uk10k project

genomic studyin uk
3700 ind eu ancestory
detect rare and low freq variation in uk pop that are in ind with disease/obestiy etc


what has the uk10k project found

576 genes with hom or hetero compound variant predicted to result in loss of pr function
one which osteoporosis variant


what has study in uk10k revealed about osteoporosis variant

id a variant also in icelandic pop
uk110k foudn 3 snps near en1 gene
show high assoc with lunbar coe defect
mouse with the variant lower bone mineral density