L6 population specific variation Flashcards Preview

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Flashcards in L6 population specific variation Deck (39)
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1
Q

how does genetic diversity arise in populations

A

variants intro by muts

lost by genetic drift

2
Q

what the relationship between diversity and age of population

A

older pop more genetic diversity

3
Q

whatcan be revealed from the genetic diversity of a population

A

age
split from ca
slection pressures within the envuroment

4
Q

hwo does geogrpahy link to genetic diversity

A

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

5
Q

what gene used as a measure of genetic diversity

A

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

6
Q

name some of the large scale sequencing studies

A

1000 genomes project

UK10k project

7
Q

what the findings of the 1000 genomes project

A
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
8
Q

what are the gentic impacts of colonisation and migration

A

founder effect

gene flow

9
Q

what is admixture

A

the creation of hybrid pop from two ancestral pop

10
Q

what the general genetic consequence of admixture

A

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

11
Q

what other consequence of admixture

A

new pathogen exposure incr disease

12
Q

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

A

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

13
Q

when did the movement into the american occur

A

15000ya

14
Q

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

A

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

15
Q

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

A

13,000ya

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

16
Q

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

A

seperate clade whihc are closer to indigenous siberians

17
Q

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

A

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

18
Q

what is population y

A

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

19
Q

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

A

aus
than e. asain/siberian
no admixture in bering strait

20
Q

what problem with conclusions from pop y at the moment

A

no ancient dna prove

although craniomorphological features of ancestral fossils support

21
Q

when and where fossil usr1 from

A

beringia alaska

dated 11.5kya

22
Q

what has fossil usr1 revelaled/suggested

A

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

23
Q

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

A

varied by countries

24
Q

what country has the highest n.am genetic sim

A

n. am

25
Q

what country has the smallest afr contribution

A

peru/chile/argentine

26
Q

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

A

eu -iberia = spain

27
Q

what findings for argentina migration / genetic input

A

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

28
Q

what findings for ecuador migration / genetic input

A

the least eu/afr input

29
Q

what have studies in south american native american shown

A
no evidence of northern native american in latin derived s.am 
there are two clusters
-central andean 
-other souther native american 
= andes geog barrier
30
Q

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

A

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

31
Q

what is the finnish disease spectrum

A

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

32
Q

what cause the finnish disease spectrum

A

geog and language barrier

33
Q

what different about y chr in finnish pop

A

diversity lower than other eu pops

34
Q

give an example of a disease of the finnish disease spectrum

A
,eckel syndrom 
auto rec 
cyctic kidney 
polydactyl
worlwide incidence 0.2 per 1000
finalnd 1.1 per 1000
35
Q

what examples of environmental adpatation in gentic diversity

A

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

36
Q

describe the fidings of enviromental adaptation in inuit pop

A

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

37
Q

what is the uk10k project

A

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

38
Q

what has the uk10k project found

A

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

39
Q

what has study in uk10k revealed about osteoporosis variant

A

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