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Meiosis—The Process that Fosters Genetic Diversity. http://www.uic.edu/classes/bios/bios100/lecturesf04am/lect16.htm. Karyotype. A display of condensed chromosomes arranged in pairs. Meiosis. A type of cell division that reduces the number of chromosomes from diploid to haploid.
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Meiosis—The Process that Fosters Genetic Diversity http://www.uic.edu/classes/bios/bios100/lecturesf04am/lect16.htm
Karyotype • A display of condensed chromosomes arranged in pairs.
Meiosis • A type of cell division that reduces the number of chromosomes from diploid to haploid. • Meiosis creates genetic diversity through crossing over and independent assortment. • Meiosis ONLY creates sex cells
Synapsis • During Prophase I, replicated homologues pair up and become physically connected along their lengths by a zipper-like protein structure (the synaptonemal complex).
Crossing Over • The exchange of corresponding segments of DNA molecules by non-sister chromatids.
Chiasma/Chiasmata (plural) • The point where crossing over has occurred and the homologs are still associated due to cohesion between sister chromatids
Interphase • Chromosomes replicate to form sister chromatids.
Prophase I • Crossing over occurs during synapsis. • Chiasma are evident
Metaphase I • Chromosomes line up by homologous pairs on the metaphase plate • Alignment is independent of maternal/paternal origin
Anaphase I • Each pair of homologous chromosomes separates
Telophase I & Cytokinesis • Two haploid cells form, each chromosome still consists of two chromatids
Prophase II • A new spindle apparatus forms
Telophase II & Cytokinesis • Four haploid, genetically unique cells form.
Telophase I & Cytokinesis • Two haploid cells form, each chromosome still consists of two chromatids
Telophase I & Cytokinesis • Two haploid cells form, each chromosome still consists of two chromatids