BIOL 341 Lecture Notes - Lecture 2: Mitochondrion, Prokaryote, Mitosis
24 Feb 2017
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Ploid(cid:455) le(cid:448)el (cid:894)(cid:862)n(cid:863)(cid:895): the (cid:374)u(cid:373)(cid:271)er of (cid:272)opies of the e(cid:374)tire ge(cid:374)o(cid:373)e i(cid:374) a (cid:272)ell. Polyploidy is very common in plants (2 forms: autopolyploids: contain multiple complete genomes of a single species, allopolyploids: contain multiple complete genomes derived from two or more separate species (interspecies hybridization) When comparing allopolyploids to their progenitors, it is difficult to determine whether phenotypic differences are due to genome duplication or to hybridization of the two species. Genetic changes seen in newly formed allopolyploids compared with their parent species: Reorganization of the genome, including loss or gain of dna sequences. Activation of previously dormant transposable elements through loss of gene silencing. Aneuploidy: contain more or fewer individual chromosomes (not entire chromosome sets) than normal: often reduced viability in humans, but generally viable in plants. Polyploid is just as common in humans as in plants, but because the effects are so damaging, the cells are terminated in the earliest stages.
