483 Lecture Notes - Lecture 6: Allosome, Zygosity, Chromosome
Document Summary
Mendel studies inheritance in peas by crossing true breeding plants and looking at several traits. The traits are controlled by two alleles in diploids. Alleles occur on homologous chromosomes at a speci c location that we call locus. Autosomes are the 22 rst pairs of chromosomes and allosomes are the sex chromosomes. Male heterogametic (female xx/male xy) > humans. Female heterogametic (female zw/male zz) > birds. The genes that are located on the x and y chromosomes di er: X chromosome : genes for everyday human function, genes for being female, >1000 genes (these genes are called sex-linked genes) Y chromosome : genes for being male, 26 genes. Sex-linkage was not observed in mendel"s experiments, because the traits studied were not sex- linked. These genes on sex chromosomes (x and y) are inherited di erently in males and females. These genes were rst discovered in drosophila (geneous) melanogaster (species) by t. h morgan. This organism feeds and breeds on spoiled fruits.