PSY 01316 Lecture Notes - Lecture 2: Sickle-Cell Disease, Intellectual Disability, Phenotype
Document Summary
Chapter 2- lecture 2- biological and environmental foundations: the genetic code. Each cell contains 23 matching pairs of chromosomes: chromosomes hold genes, the basic unit of heredity, genes are composed of dna (deoxyribonucleic acid) Zygote- fertilized egg (sperm and ova: sex chromosomes determine whether zygote will develop into a male(xy) or female (xx) Dominant genes are always expressed regardless of the gene they are paired with. Recessive genes are only expressed if pairs with another recessive gene. When an individual is heterozygous for a particular trait, the dominant gene is expressed and the person becomes a carrier of the recessive gene: genetic inheritance processes. Incomplete dominance- a genetic inheritance pattern in which both genes influence the characteristic (blood type: one heterozygous allele is stro(cid:374)ger tha(cid:374) the other but does(cid:374)"t totally dominate (sickle cell anemia) Genomic imprinting- gene expression determined by inheritance from mother or father (prader-willi/ a(cid:374)gel(cid:373)a(cid:374)"s sy(cid:374)dro(cid:373)es)
