ENVS 2210 Lecture Notes - Lecture 12: X Chromosome, Mitosis, Charles Dadant
15 Nov 2016
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Document Summary
Genes, sex determination and their consequences in honeybees. Black eyes are dominant colour they see; red is recessive. Mitosis in somatic cells = 2 identical diploid cells: diploid b/c queen has 2 sets of chromosomes. Meiosis in germ cells = 4 genetically different haploid cells: haploid = drones b/c they have 1 set of chromosomes. Females = xx (homozygous) ; males = xy (heterozygous; one x chromosome from mothere, one y from father) Females carry only x chromosomes; males may carry chromosome x or y (males determines the sex of the child) Most genes have only 2 forms (alleles) or expression. Sex determined by a gene and not by a chromosome. Sex gene in bees has more than 15 alleles (15 expression forms). When two alleles of the sex gene are the same (homozygous genotype) the resulting individual is a diploid gene. Diploid drone larvae are eaten up by worker bees; diploid females are not.
