BIOL10005 Lecture Notes - Lecture 7: Precocious Puberty, Homologous Chromosome, X-Inactivation
31 Oct 2018
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Document Summary
Independent assortment and gene interaction: turner syndrome & abnormalities, both x chromosomes are active until 500 cell stage, not all genes are inactivated. Expected ratio of hemophilia a is 1:1. Due to over 50% of cells having xh inactivated. Heterozygous female with a particular disease (such as dmd, duchenne muscular. Dystrophy) can show mild symptom of the phenotype due to atypical x inactivation: sex influenced traits. The phenotypic expression (located on autosome) is influenced by the sex of the individual e. g. ) Only expressed in one sex but can be transmitted by either sex) e. g. ) Earlier puberty = taller when young, but stops growing earlier. One pair of homologous chromosome behaves independently relative to other pairs of chromosomes. Organism needs more than 1 pair of chromosomes. Number of different gametes for humans, 2n, 223. Shows if a gene is assorting independently or autosomally linked. If the genes are assorting independently -> ratio of 1:1:1:1: gene interaction.
