freepeople性欧美熟妇, 色戒完整版无删减158分钟hd, 无码精品国产vα在线观看DVD, 丰满少妇伦精品无码专区在线观看,艾栗栗与纹身男宾馆3p50分钟,国产AV片在线观看,黑人与美女高潮,18岁女RAPPERDISSSUBS,国产手机在机看影片

正文內(nèi)容

qtl定位的原理和方法-資料下載頁(yè)

2025-05-15 23:14本頁(yè)面
  

【正文】 ur haplotype frequencies is zero, = 1. 23:13 3. For biallelic markers, another useful measure is(Hill and Robertson, 1968): – Nr2 is the test statistic for independence as calculated from a 2x2 contingency table. – A statistical test of LD using the r2 statistic is therefore straightforward. 2?23:13 Measures of LD for multiallelic marker ? Hedrick, 1987: 23:13 – k and l are the number of alleles at locus A and B. – pAi and pBj are the population allele frequencies of allele i at locus A and allele j at locus B. – |D‘ij| is the absolute value of the normalised measure. – pAiBj is the estimated population frequency of the haplotype AiBj – Dijmax is the maximum amount of disequilibrium possible between allele i at locus A and allele j at locus B. ? The corresponding multiallelic measure of the squared correlation is: 23:13 linkage disequilibrium vs. gametic phase disequilibrium ? The term linkage disequilibrium appears to imply that the loci have to be linked. ? However, this is not the case, because an association between alleles can exist even if the alleles are unlinked. – two populations with unequal frequencies are mixed. – Nonrandom mating. – the case of an F1 population. – Selection ? A better term for LD is ?gametic phase disequilibrium‘, which is used in text books such as Falconer and Mackay (1996) and Lynch and Walsh (1998) 23:13 D’ or r2? ? Hedrick (1987) stated that a good measure of disequilibrium should have the following properties: – A simple biological interpretation. – Statistical tests should be possible. – Be directly related mathematically to evolutionary factors such as rebination, selection, geic drift, gene flow etc – Be standardised to allow parisons across loci or populations 23:13 Dynamics of LD ? There are a number of evolutionary forces that create LD, including mutation, admixture (crossbreeding), geic drift, inbreeding, founder effects and selection. ? The main force that destroys LD is rebination. 23:13 23:13 LD mapping ? mapping requires a marker to be in LD with a QTL across the entire population. To be a property of the whole population, the association must have persisted for a considerable number of generations, so the marker(s) and QTL must therefore be closely linked. 23:13 23:13 ? The difference between Linkage and LD analysis: – linkage analysis uses LD within families whereas LD analysis uses LD in the whole population. – In linkage studies, information is observed on alleles shared by descent (IBD), whereas in LD mapping studies, in the absence of known pedigree information, we can only observe alleles shared by state (IBS). – For linkage analysis we have observed rebination events and realised genomic relationships between individuals in the pedigree, whereas for LD analysis the rebinations occurred in the recent or distant past and we are trying to infer them from data. 23:13 Genome wide association tests using single marker regression ? It is suitable for a random mating population with no population structure 23:13 single marker regression with considering population structure 23:13 Genome wide association using haplotypes 23:13 IBD LD mapping 1?????? ? ? ???? ? ? ???? ? ? ?? ? ? ? ???? ? ? ?? ? ? ????? ? ? ? ?? ? ? ?n n n n n1n11n2162。 162。 162。 162。1 1 1 Z 1 W 1 yu Z 1 Z Z + A λ Z W Z yg W 1 W Z W W + G λ Wy23:13 Combined LDLA mapping ? Authors investigating the extent of LD in both cattle and sheep were somewhat surprised/alarmed to find not only was LD highly variable across any particular chromosome, but there was even significant LD between markers which were not even on the same chromosome! 23:13 Combining method ? If the mon ancestor occurs within the known pedigree, then IBD probability can be calculated from the markers by linkage analysis (LA) ? If the mon ancestor is outside the known pedigree it is a source of this case the probability that the QTL alleles are IBD is calculated from the similarity between the marker haplotypes, ., which marker alleles have both haplotypes in mon 23:13 23:13
點(diǎn)擊復(fù)制文檔內(nèi)容
研究報(bào)告相關(guān)推薦
文庫(kù)吧 www.dybbs8.com
備案圖鄂ICP備17016276號(hào)-1