Introduction to Genetic Analysis 675

Introduction to Genetic Analysis 675 - the amount of...

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Unformatted text preview: the amount of difference between the offspring and the unselected parents (realized selection progress). If there is no selection progress, the heritability is zero. If the se- lection progress is equal to the selection differential, the heritability is unity. Do many loci (or only a few) vary with respect to the character? How are they distributed over the genome? An estimate of the number of loci that influence the ob- served variation in a character is made from the results of linkage studies with known genetic markers distrib- uted across the genome. If a detectable proportion of the differences between individuals in the quantitative char- acter segregates together with the allelic differences at a marker gene, then a quantitative trait locus (QTL) has been detected near the marker gene. Manyperhaps mostof the phenotypic traits that we observe in organisms vary continuously. In many cases, the variation of the trait is determined by more than a single segregating locus. Each of these loci may con- tribute equally to a particular phenotype, but it is more likely that they contribute unequally. The measurement of these phenotypes and the determination of the con-...
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.

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