Synapsis is the pairing of homologous chromosomes during meiosis. Occurs during prophase I of meiosis. Chromosomes attach to nuclear envelope and migrate to match ends. Synaptonemal complex (SC) stabilizes physical pairing
Chiasma is the physical link between non-sister chromatids on homologous chromosomes. Chiasmatypie was discovered by Frans Alfons Janssens in 1909
Chromosomal translocation involves unusual rearrangement of chromosomes. Reciprocal translocation exchanges parts between non-homologous chromosomes. Robertsonian translocation occurs when two non-homologous chromosomes fuse. Translocations can be balanced (no genetic changes) or unbalanced
Crossing over exchanges genetic material between homologous chromosomes during meiosis. Occurs in pachytene stage of prophase I during synapsis. First described by Thomas Hunt Morgan in 1912. Physical basis demonstrated by McClintock and Creighton in 1931
23 is the ninth prime number and smallest odd prime not twin prime. Sum of first 23 primes is 874, divisible by 23. Contains 23 prime factors and is a member of first prime sextuplet. Forms basis for Leech lattice through which 23 other Niemeier lattices are built
Polyploidy occurs when cells have more than two sets of chromosomes. Most eukaryotic species are diploid, having two complete chromosome sets. Monoploids have only one set of chromosomes, like male bees