BIOL 111 Lecture : week 11.3.docx
Document Summary
Learning outcome: you will be able to figure out the genotypes and phenotypes of offspring based on the phenotypes and genotypes of their parents. Down syndrome: one in 733 babies born have down syndrome. Individuals with down syndrome are sterile and have other health issues such as heart defects and susceptibility to respiratory infections. They are also prone to develop leukemia or alzheimer"s disease. Some gametes have extra chromosomes or fewer chromosomes than they are supposed to have. The likelihood of having a child with down syndrome increases with the mother"s age. Due to the increasing high risk, pregnant women over 35 are candidates for fetal testing to check the chromosome of their embryo. Other genetic abnormalities that may be due to problems in meiosis include turner syndrome (xo), klinefelter syndrome (xxy), or cri du chat (some part of chromosome 5 missing).
