PSYCH 1XX3 Lecture Notes - Lecture 2: Twin Study, Zygosity, Behaviorism
28 Feb 2017
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Document Summary
From conception, a zygote is formed containing 46 chromosomes (26 from each parent) Chromosome made of dna, segments of dna contain genes, contain 30,000-40,000 genes. Zygote divides at an exponential rate, born with billions of cells with all 46 chromosomes. Monozygotic twins: genetically identical, same sperm and ovum, same zygote that is split into two. Dizygotic twins: share ~50% of genes, similar genetics as two siblings, different sperm and ovum, two different zygotes from the moment of conception. Phenotype the expression of an individual"s genotype in terms of observable characteristics. Genotypes can express into different forms of phenotypes. A phenotypic trait is often governed by multiple pairs of genes (i. e. eye colour) Four main patterns of genetic expression: simple dominant-recessive inheritance. A pattern of inheritance in which the expression of a trait is determined by a single pair of alleles. Homozygous: when two alleles have the same effect on the phenotype.
