PSYCH 1XX3 Lecture Notes - Lecture 2: Sensation Seeking, Egg Cell, Zygosity
9 Mar 2016
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Document Summary
Chromosomes and genes: zygote has 46 chromosomes, 23 from each parent. Cell division: grows by dividing exponenially, each parent can produce more than 8 million diferent geneic combinaions, leading to produce in theory 64 trillion geneically disinct ofspring, monozygoic twins. Sex chromosomes as many genes in common as regular siblings: male is xy, female xx, female always passes on x, male determines gender. The expression of an individual"s genotype in terms of observable. 4 paterns of geneic expression characterisics: simple dominant-recessive inheritance. Homozygous: when 2 alleles have the same efect on the phenotype. Heterozygous: when 2 alleles have diferent efect on the phenotype. Dominant allele is expressed in the phenotype. Recessive allele not expressed but sill heritable: polygeneic inheritance. Characterisics determined by muliple genes which is complex: codominance. 2 dominant alleles both fully and equally expressed to produce phenotype that is a compromise between the 2 genes. Abo blood (a and b dom, o recessive: sex-linked inheritance.
