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GENE MAPPINGPOLYMORPHIC MARKERS AND LINKAGE ANALYSIS

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GENERAL CONCEPTS

A prerequisite for successful lin!"e !n!l#sis is t$e !%!i! l!r"e nu'&er of $i"$l# pol#'orp$ic '!rers (t$rou"$out t$e "eno'e) T$ere !re se%er!l cl!sses pol#'orp$ic '!rers !n( o%er 20,000 of t$ese pol'!rers $!%e no* &een i(enti+e( !n( !re !%!il!&le forstudies.

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DI,,ERENT TYPES O, DNAPOLYMORPHISMS

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DI,,ERENT TYPES O, DNAPOLYMORPHISMS

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RECOM-INATION AND LINKA

Linkage: Alleles of t*o loci t$!t !re liel# to &e in$erite( to"et$er)M: M!rer .SRTP/

2loci

2allele

MEIOSIS

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RECOM-INATION AND LINKA

Crossover

Hapco'on !c$ro

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RECOM-INATION AND LINKA

RECOMB!"#O! $RE%&E!C'T$e closer to 0(reco'&in!tion frequenc# is0 t$e closer t$e)arker is to t$e gene.

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RECOM-INATION ,RE12ENCY ANDGENE MAPPING

!euro*+ro)atosis gene

isease - "

!or)al - a

2

",a2

",a2

a2,a2

a,a

",aa,a2

Noreco'&in!tion

T$e "ene is L!1Eto t$e '!rer3 t$e# !re in$erite( to"et$er 'ore t$!n $c!ses)

Out of 4 c$il(ren in "ener!tion III0 one is reco)+inant .!5 fro' 'ot$er/)

Reco'&in!tion frequenc# is 564 7 8)59 7 ( .(ist!nce &et*een : loci/

( - centiMorgan /cM - )illion +p

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LOD SCORES

LO: Pro&!&ilit# t$!t t$e "ene !n( t$e '!rer !re line( to"et$er)A LOD score ; < in(ic!tes lin!"e)

A LOD score = : in(ic!tes no lin!"e)

T$e %!lue of R, !t *$ic$ t$e $i"$est LOD score is seen is t$e 'ostesti'!te of t$e reco'&in!tion frequenc#)

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GENETICDIAGNOSISINDIRECT >S DIRECT DIAGNOSIS

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irect diagnosis: Mut!tion itself is e?!'ine()

ndirect diagnosis: line( '!rers !re use( to infer *$et$er in(i%i(uf!'il# $!s in$erite( t$e (ise!se@c!usin" !llele)

PCR

Dot -lot !n( ASO

R,LP

DNA sequencin"

Mutatedgene

MarkerPCRR,LPSRTP

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DOT -LOT .ASO/"3O: Allele speci+c oli"onucleoti(e)&se 2 di4erent "3O pro+es

.58 B :8 oli"onucleoti(es/) 5 reco"nie nor'!l !llele)

5 reco"nie 'ut!nt !llele)

He)oc5ro)atosis'ut!tion in HFE "en

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H

!

C

R

H

M

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.DIRECT/ R,LP

5F8 &p

PCR

Hph1

o

r55

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INDIRECT DIAGNOSIS 2SING STRPs3R#7 '!rer .%ersion 50:0

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INDIRECT TESTING 2SING R,LP

;7 Nor'!l !lle

;IGNETTES

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"7 (ise!se!llele

a7 nor'!l!llele

a

a

a

aa"

"

a

aa

a"

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