LIFE 102 Study Guide - Quiz Guide: Thomas Hunt Morgan, Mendelian Inheritance, X-Inactivation
Document Summary
Recessively inherited disorders show up only in individuals homozygous for the allele. Carriers are heterozygous individuals who carry the recessive allele but are phenotypically normal (i. e. , pigmented) Albinism is a recessive condition characterized by a lack of pigmentation in skin and hair. Some human disorders are caused by dominant alleles. Dominant alleles that cause a lethal disease are rare and arise by mutation. Achondroplasia is a form of dwarfism caused by a rare dominant allele. In amniocentesis, the liquid that bathes the fetus is removed and tested. In chrionic villus sampling (cvs), a sample of the placenta is removed and tested. Other techniques, such as ultrasound and fetoscopy, allow fetal health to be assessed visually in utero. Concept 15. 1: mendelian inheritance has its physical basis in the behavior of chromosomes. Mitosis and meiosis were first described in the late 1800s. Mendelian genes have specific loci (positions) on chromosomes.
