BIOL 2040 Lecture Notes - Lecture 17: Patau Syndrome, Down Syndrome, Edwards Syndrome
Document Summary
Most common aneuploidys are for sex chromosomes. Smaller the chromosome pair, the less the probability it will contain very important genes. These individuals can survive, but not live healthy lives and usually die young. Karyotype notation: [45, xx, -21] = 21 monosomy female: male/meiosis 1, female/meiosis 1, male/meiosis 2, female/meiosis 2, during meiosis 1, during meiosis 2. ** be able to draw meiosis quickly for tests/exam! Meiotic tetrad (bivalent): 1 homologous pair = 4 dna molecules = 2 pairs of sister chromatids. Synaptonemal complex: formed when zip 1 and zip 2 bring homologous pairs of chromosomes together. This occurs at synapsis , the alignment of homologous pairs during meiosis metaphase i: cause specificity in homologous pairs, also important for recombination. Recombinant: when there has been crossing over between one sister chromatid from separate homologues. Parental: gametes formed when crossing over does not occur.
