BIO207H5 Study Guide - Comprehensive Midterm Guide: Erwin Chargaff, Semiconservative Replication, Francis Crick
Document Summary
Humans have been aware of genetics, via selective breeding, for over 10,000 years. Exploration and understanding of the principles of heredity is a more recent development. An amateur botanist named gregor mendel published an explanation of hereditary transmission in plants in 1866. His work was independently rediscovered in 1900 by three botanists: correns, de vries, and von tschermak. Garrod (1901) described the inheritance of a disorder called alkaptonuria in humans. Bateson, a proponent of (cid:862)mendelism,(cid:863) recognized that the trait must be a (cid:862)rare, recessive character(cid:863) Soon after, sutton and boveri independently observed chromosome movement during cell division. Genes are the physical units of heredity, as originally posited by mendel; now known to be defined dna sequences. Chromosomes are long molecules of double-stranded dna and protein, which contain genes. Sexually reproducing organisms usually have homologous pairs (or homologs), two of each chromosome. The single bacterial chromosome, found in the nucleoid, replicates in conjunction with cell division.
