Chapter 3 Human Genetics

Chromosomes have specialized regions at their ends that keep chromosomes from sticking to each other

Prophase 1, metaphase 1, anaphase 1, telophase 1

Prophase II, metaphase II, anaphase II, telophase II

Chromosomes fail to separate properly during one of the two divisions in meiosis; some gametes have two copies of the same chromosome

Variations in chromosome number that involve one or a small number of chromosomes; leading cause of mental retardation and developmental disabilities

Used to analyze the fetus' chromosomes and detect any abnormalities
Performed at or after the 16 week of pregnancyà takes 7-14 days

Used when: the mother is 35+, the mother had a child w/ chromosomal aberration, each parent has 1+ structurally abnormal chromosomes, the mother is a carrier of a genetic disorder, the parents have unexplained infertility/previous miscarriages

Fluid surrounding the fetus

Chromosomes 1-22 (autosomes) are arranged in pairs; sex chromosomes are placed on the karyotype separately

Cells of chorionic villi are removed by suction and analyzed; another method of prenatal chromosome analysis; can be performed earlier in the pregnancy; test results available within few hours or few days

Additional copies of all chromosomes in a cell

Diploid number (2n or 46 chromosomes) in body cells and haploid number (n or 23 chromosomes) in gametes are the normal condition

Gain of one chromosome

Loss of a single chromosome

Trisomy and monosomy

Most common cause of trisomy and monosmy; failure of chromosomesto separate properlyduring meiosis