BIOLOGY 3 Lecture Notes - Lecture 3: Genetic Counseling, Intellectual Disability, Phenylalanine
Document Summary
Involve a sperm and/or egg lacking a normal set of 23 chromosomes. Can have too many, or too few. Women 16 34 significantly less likely to have children with down syndrome. Left untreated, phenylalanine builds up in the child producing mental retardation and hyperactivity. Red blood cells become sickle shaped and cannot carry oxygen properly. 1 in 10 are carriers, 1 in 20 latin-americans are carriers. Every individual carries dna variations, but most do not display a disorder. Many chromosomal & genetic abnormalities can be detected prior to & immediately after birth. Knowledge of defects leads to difficult decisions. Provide information for couples to make informed decisions. Seeks to discover the influence of heredity and environment on individual differences in human traits and development. Twin studies: compare identical and fraternal twins. Adoption studies: compare characteristics of adopted children with their adoptive parents and their biological parents. May also compare adopted and biological siblings.
