BSCI 105 Lecture Notes - Lecture 13: X-Ray Crystallography, Pyrimidine, Purine
11 Jul 2016
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Heritability offspring resemble parents: phenotypes, phenotypic variation individuals have differences in traits, heritable variation differences in traits that get passed on to offspring. Gene a unit of heritable material that defines a trait. Alleles different versions of a gene that explain variations in a trait: genotypes. Asexual reproduction: variation occurs between clonal lineages of an organism, offspring and parents look exactly the same. Sexual reproduction: variation occurs between individuals, offspring resemble a mix of parental traits. Genetically blended : produces new combinations of heritable variations in traits, involves combination of gametes. Diploid-haploid alternation: somatic cells have 2 copies (homologues) of every chromosome. Humans: 2n = 46; diploid: gametes have one copy of every chromosome. Humans: 1n = 23; haploid: gametes combine to form an embryo with two copies back to diploid. Hammerling (1930: graft experiment, nucleus determines phenotype, nucleus contains chromosomes that replicate and divide between cells. F. griffith (1920: demonstrated transformation, genetic material transferred between strains.
