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Prophase I
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Chromosomes condense, homologous pairs align, synapsis (precise alignment, ensires 1 copy of each gene in a daughter cell). Synapsed set called a tetrad (4 chromatids). Then, crossing-over occurs (exchange of chromosome segments between pairs of homologous chromosomes, or nonsister chromatids). Chiasma forms, visible structure from crossover. X and Y chromosomes pair and synapse thru terminal ends (PARs).
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2N
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Metaphase I
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Nucleoli and envelope broken down, centroiles w/ spinde enternuclear area, kinetechore microtubules attach to sister kinetochores, tetrads align at metaphase plate.
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2N
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Anaphase I
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Chromosomes of tetrad separate (now dyads). Sister chromatids remain attached at centromeres. DNA content is halved.
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2N-N
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Telophase I
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Spindles dissasemble, cytokinesis forms two haploid cells.
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N
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Prophase II
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Chromosomes condense and spindles form, kinetochores attach to tubules..
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Metaphase II
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Alignment on metaphase plate.
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Anaphase II
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Centromeres separate, daughter chromosomes (still haploid) pulled to opposite sides.
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Telophase II
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Chromosomes decondense, nuclear envelope forms, cytokinesis. Four haploid cells produced, each with one chromosome from each homologous pair.
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Haploid
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ONE copy of each chromosome. (N)
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Diploid
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TWO copies (homologues) of each chromosome. (2N)
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Homologous pairs
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Same gene loci, structure, and pair during meiosis.
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Allele
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Alternative forms of a single gene on the same locus that determine the same trait, but can produce different phenotypes.
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Informative cheat sheet, well worth reading. It would be easier to understand if you included a short dictionary.
Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
