BIOL 117 Lecture Notes - Lecture 3: Ploidy, Karyotype, Trisomy
Document Summary
Does not necessarily always give you gametes in other animals, but in humans they do: for honeybees, male gametes are formed through mitosis. Down syndrome: three chromosome 21s (trisomy 21, many developmental and health effects resulting. Humans - diploid (one chromosome from mother and another from father): 2n = 46. Sexual reproduction: two parents with unique offspring: offspring are similar to parents but not identical, combines the dna (aka the characteristics) of two individuals. Meiosis = reductive division (ex. if it is a 2n diploid, the gametes would have n: there is recombination later on which gives offspring the 2n diploidity once the n+n combine. Calculate number of possible gametes = 2^23 for humans: in order to calculate, do 2 to the power of how many chromosomes there are. Crossing over adds additional variation to dna passed down to the offspring: adds even more variability to the process.
