Bio 201 S14 Class 5 2 5 14 v2

X x x x x muta1ons occur and accumulate reversal

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Unformatted text preview:   One diploid cell (2N) duplicates its chromosomes (“4N”) and then undergoes two divisions, resul1ng in four haploid (N) gametes SLIDE 12 Meiosis Pre- meio1c cell 2N in this example N=2 chromosomes chromosome replica1on (S- phase: synthesis) 4N Chromosomes from mother: red Chomosomes from father: blue pole Independent 1st Meio1c division “Meiosis I” assortment also occurs in meiosis 2N Process determining blue and red 2N pairs in each 4N eio1c ivision tetrad going to one 2nd MMeiosis dI” “ I pole or other is random pole Meiosis I metaphase Crossing over (recombina1on) Some chromosomes are “recombinant” SLIDE 13 Four haploid gametes Mul1cellular eukaryote reproduc1ve diversity: alterna1on of genera1ons between haploid and diploids •  One group that does this: land plants and many other mul1cellular photosynthe1c eukaryotes gametophyte sporophyte see LIFE 9th ed. Fig. 27.13 SLIDE 14 recombina1on •  Mendel’s law of independent assortment is a type of recombina1on •  Formally, meio1c recombina1on, or “crossing over”, involves exchanges between homologous chromosomes prior to the first division of meiosis SLIDE 15 SLIDE...
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This document was uploaded on 04/03/2014 for the course BIO 201 at SUNY Stony Brook.

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