PSYCH 1XX3 Lecture Notes - Lecture 2: Allosome, Egg Cell, Twin
18 Apr 2017
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Document Summary
Genetic information and environmental stimuli interact to shape who we become. Chromosomes: a thread-like structure made up of dna: a single human cell contains 46 chromosomes, 23 from each parent; consists of many genes. Monozygotic twins: same sperm and ovum, genetically identical. Dizygotic twins: different sperm and ovum, share 50% genes. The male provides the genetic information that determines the sex of an infant. Autosomes: 22 are similar in males and females. Sex chromosomes (m/f difference): 23rd chromosome which determines a person"s gender. There are four main ways by which genetic information is expressed as a phenotype. Phenotypes: the expression of an individual"s genotype in terms of observable characteristics: 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 a different effect on the phenotype.
