BIOL239 Lecture 4: BIO 239 Set 4
Document Summary
1854 studies with frogs and sea urchins showing union of male and female gametes. 1879 observation of threadlike structures in the nuclei of salamander cells during cell division. 1880 advances in microscopic techniques use of dyes for differential staining of cytoplasm, nucleus and nuclear structures, including chromosomes. Early 1900s linking of chromosomes to mendelian principles of segregation and independent assortment proposed that each egg or sperm contains only one of each chromosome of a pair chromosomal theory of inheritance. Chromosomal theory of inheritance: states that hereditary information is on genes and that genes are located on chromosomes. Also that egg and sperm contribute equally to the genetic endowment of offspring through their nuclei. 1901 the x and y chromosomes determine sex in grasshoppers. Xxxxxyyyyy not all xs and ys are homologous. Dros: female male male dies dies female male. Hum: female male turner female dies female klinefelter male male.