HLTC23H3 Chapter Notes - Chapter 3: Prenatal Development, Radiography, Eyelid
Document Summary
The biology of heredity: each meiotic division in girls results in the production of one, viable egg and three that die off immediately, each meiotic division in boys produces four sperm. 20% of in vitro fertilization succeeds: likely to have twins or triplets, genotype along with environmental influences makes up a person"s phenotype. Behavioural genetics: polygenic inheritance, when phenotypes reflect the combined activity of many separate genes, we cannot trace the contribution of each gene directly. Fatal disease characterized by progressive degeneration of the nervous system adulthood. Develop normally through childhood, adolescence, and young. Middle age, nerve cells begin to deteriorate: muscle spasm, depression, and significant changes in personality, usually occur after having children and these children mostly go on to develop this disease themselves. Inherited disorders are rare: 1 in 10 000 or more, more common are disorders caused by the wrong number of chromosomes.
