PCB 4674 Lecture Notes - Lecture 3: Gamete, Parthenogenesis, Ploidy
2 Sep 2016
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Sources of variation (chapter 5) continued: duplicated genes. Genes duplicated by crossing over or replication slips usually contain introns and regulatory regions often located right next to original gene: genes duplicated by retroposition usually lack introns and regulatory regions often located far from original gene. Pseudogenes : may acquire functionality if inserted near regulatory regions, horizontal transfers. Vertical transfer parent to offspring no new genetic material. Mutations in previously non-coding dna e. g. human c22orf45. 5 sets are polymorphic for inversions e. g. different flies have different sets of supergenes. Problems with segregation during meiosis can lead to diploid germ cells: which would ordinarily be haploid. Tetraploid x diploid = triploid offspring often not viable, usually sterile. Tetraploid x self = tetraploid viable and fertile: may provide selectable variation, especially as relates to range expansion. Subsequent isolation between organisms of different ploidy may lead to new species: mutations and evolution.
