Sexual Reproduction And Clues To Chromosome Crossovers
Date: 7.3.2013
Neil Hunter's laboratory in the UC Davis College of Biological Sciences has placed another piece in the puzzle of how sexual reproduction shuffles genes while making sure sperm and eggs get the right number of chromosomes.
The basis of sexual reproduction is that a fertilized egg gets half its chromosomes from each parent - sperm and eggs each contributing one partner in each pair of chromosomes. We humans have 23 pairs of 46 chromosomes: so our sperm or eggs have 23 chromosomes each.
Before we get to the sex part, though, those sperm and eggs have to be formed from regular body cells that contain twice as many chromosomes. That happens through a specialized type of cell division, meiosis.
During meiosis, the couples in each pair of chromosomes have to, well, couple by "crossing over" with each other. Each chromosome pair must become connected by at least one crossover so that when the couples separate, they are delivered to separate sperm or egg cells...
