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A kinship based method of measuring genetic diversity Herwin Eding ID-Lelystad Lelystad, The Netherlands
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Short outline of presentation Definition of genetic diversity Why kinships? Marker Estimated Kinships –Similarity index –Accounting for probability AIS Core set diversity Application
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Definition Genetic Diversity Maximum genetic variation of a population in HW-equilibrium derived from a set of conserved breeds
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Kinships and genetic diversity (1) V Gw = V G [1 – f w ] –(Falconer and MacKay, 1996) Diversity proportional to (1- f W ) Max(diversity) => min(f W )
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Kinships and genetic diversity (2) Kinship coefficients from pedigrees Between breed diversity –Within breed diversity relative to others No/insufficient administration => Use marker information
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Marker Estimated Kinships 1.Similarity score Based on definition Malecot, 1948 2.Correction for alleles Alike In State 1.not IBD
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Marker Estimated Kinships (2) Similarity Index If Prob(AIS) = 0, E(S xy ) = f xy Genotype xyS xy AAAA1 AAAB½ ABAB½ ABBC¼ ABCD0
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Marker Estimated Kinships (3) Correction for alleles Alike In State (AIS) When Prob(AIS) > 0 –S ij,l = f ij + (1 –f ij )s l = s l + (1 –s l )f ij s l = Prob(AIS) for locus l Estimate: –f ij = (S ij,l – s l )/ (1 –s l )
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Marker Estimated Kinships (4) Definition of value of s Assume a founder population P, in which all relations are zero –S(P) = s + (1 – s)f P = s s l = sum(q il 2 ), where q il allele frequency in P –If (A,B) oldest fission: s = mean(A n, B m ) Where n populations in cluster A and m populations in cluster B
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Marker Estimated Kinships (5) Linear estimation of s and f ln(1 - S) = ln[(1-f)(1-s)] = ln(1-f ) + ln(1-s ) BLUP-like model: –ln(1-S ijl ) = ln(1- f ij ) + ln(1-s 0,l ) – Y ij,l = ( Z + X ij a ) + X l b
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Marker Estimated Kinships (6) Mixed Model: – = between and within population mean kinship – W = var[ln(1-S ijl )], gives priority to more informative loci – I = to regress f ij back to mean
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Core set diversity (1) c’Mc = mean(Kinship) –if c’Mc is small, genetic diversity is large Adjust c so that average kinship is minimal
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Core set diversity (2) Definition of genetic diversity The genetic diversity in a set of populations: –Div(M)= Div(cs) = 1 - f cs Describes fraction of diversity of founder population left. –f P = 0 -> Div(P) = 1
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Application 10 Dutch cattle populations 11 Microsatellite markers Breeds Abrev.Marker loci# alleles Belgian BlueBBLBM18247 Dutch Red PiedDRPBM211312 Dutch Black BeltedDBBETH0109 LimousineLIMETH2258 Holstein FriesianHFETH00311 GallowayGALINRA2311 Dutch FriesianDFSPS1157 Improved Red PiedIRPTGLA12223 Blonde d'AquitaineBATGLA1268 HeckHCKTGLA22714
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Application (2) Kinship tree
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Application (3)
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Application (4)
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Conclusions (1) Genetic diversity and kinships Defined: Gen Div V G,W V G,W = (1 - f W )V G Gen Div proportional to (1 - f W ) Core set = Set with minimum mean kinship
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Conclusions (2) MEK and genetic diversity Kinship matrix from MEK: –AIS –Definition of founder population Measure between and within population diversity
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Conclusions (3) General Not computer intensive –In theory no limits to N breeds –Extend to individuals Results are promising
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