SBasir Per. 8

1. Human Cloning: Are You For It or Against It? By Samiyah Basir Per. 8

4. Genetic Disorders Single gene disorder Chromosome abnormalities Multifactorial disorders What they have in common *Hereditary disorder caused by a mutant allele of a single gene. *Single gene disorders are inherited through dominant, recessive, and sex linked traits. *Examples: sickle- cell disease, cystic fibrosis, Huntington's disease, and Marfan syndrome. *Caused by errors and changes in the amount of chromosomes during cell division, the formation of reproductive cells, and meiosis. *Most chromosome abnormalities are not passed down to the following generation. *Examples: Down syndrome (an extra copy of chromosome 21), and Turner syndrome. *Conditions caused by mutations in multiple genes, and many contributing factors that are more complex, as apposed to single gene disorders. *Are difficult to predict whether or not a person will inherit or pass on these disorders because the specific factors that cause them haven't been identified yet. *Examples: diabetes, heart disease, cancer, and Alzheimer's disease. *Disease occurs when genes are unable to work properly. *Not all genetic disorders are evident at birth, but may become evident due to specific environmental factors that make contact with the gene. *Genes (located on chromosomes) may be copied incorrectly.