BIOC16H3 Lecture Notes - Lecture 8: Ipomoea Purpurea, Primula Vulgaris, Linkage Disequilibrium
25 Apr 2013
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To now we"ve been dealing with single phenotypic traits! Method to understand genetics and evolution of a group of traits simultaneously! Pleiotropic effects: one locus affects more than one trait! Eg: morning glory ( ipomoea purpurea) simmons and bucher 1996! W locus has pleiotropic effects on oral color and toxicity: pleiotropy, linkage! Consider 2 genes a and b - each has 2 alleles a1a2 and b1b2! p1 f(a1). q (b1)! p2 f(a2) q(b2)! When the random association isn"t observed we call it linkage disequilibrium! Mixing of maternal and paternal genes into new combinations in offsprings! Two instances: 1) meiosis- prophase 1- chromosomes pairing up! Crossing over: random probability that the maternal or paternal chromosomes of each homologous pair line up on either side of metaphase plate. If two loci are unlinked (ie. different chromosomes) the probability of recombination between them is 0. 5 ( highest amount of recombination and this number decreases as things become more linked)!
