Biology 1201A Lecture Notes - Dihybrid Cross, Homologous Chromosome, Y Chromosome
6 Dec 2012
School
Department
Course
Professor
Document Summary
Introduction: it was not until 1900 that biology nally caught up with gregor mendel, independently, karl correns, erich von tschermak, and hugo de vries all found that. Mendelian inheritance has its physical basis in the behavior of chromosomes during sexual life cycles: around 1900, cytologists and geneticists began to see parallels between the behavior of chromosomes and the behavior of mendel s factors. Chromosomes and genes are both present in pairs in diploid cells. Homologous chromosomes separate and alleles segregate during meiosis. Fertilization restores the paired condition for both chromosomes and genes. Drosophila melanogaster: small and easily reared in the laboratory, short life cycle. A new generation every two weeks: a female lays hundreds of fertilized eggs during her brief life span. The resulting large populations make statistical analysis easy and reliable: giant (polytene) chromosomes -salivary glands of the mature larvae. Morgan spent a year looking for variant individuals among the ies he was breeding.
