HSC 4555 Lecture Notes - Lecture 6: Meiosis, Albinism, Fetus
Document Summary
In humans, genes are organized into 46 different chromosome units (23 pairs). One member of each pair is inherited from the mother, and the other is inherited from the father (pg. Pedigree analysis is used to trace the transmission of a single-gene trait through the history of a family. A pedigree chart demonstrates family relationships and members that have a certain trait. Autosomal recessive traits are only expressed in the homozygous condition, thus unaffected parents can have affected male and female offspring, whereas two affected parents will result in all of the offspring being affected. If the trait is inherited as x-linked (typically recessive), generally only males will be affected (pgs. Normally, meiosis results in four daughter cells, each having one-half the normal number of chromosomes (23). Nondisjunction and anaphase lag, which can occur during meiosis, can lead to an abnormal number of chromosomes, termed aneuploidy.
