Nondisjuncti on Homologous pairs do not move apart during Meiosis

Nondisjuncti on aneuploidy- abnormal number -2n + 1 ex. Down’s trisomic - 2n - 1 ex. Turner’s monosomic

Turner’s Syndrome trisomic monosomic

Trisomy 21 Trisomic 2n + 1

Down Syndrome / Trisomy 21

Turner Syndrome X monosomic 2n - 1

Klinefelter’s Syndrome u 2N + 1 (2N + 2, 2N + 3) u Genotype u Genotype: XXY (XXXY, XXXXY) u Phenotype u Phenotype: male, but sexual development may be poor. Often taller than average, mental development fine (XXY), usually sterile. u More X = more mental problems

Kleinfelter’s Syndrome

Klinefelter’s Syndrome Comment: I have read that George Washington may have had Klinefelter’s. Taller than average, no children

Trisomy X u 2N + 1 u Genotype: XXX u Phenotype: taller female, but sexual development poor. (Mental impairment common in many reports, not in others???)

Edward’s Syndrome

Also known as Trisomy 18 Almost every organ system is affected. 1:10,000 live births. Children with full Trisomy 18 generally do not live more than a few months. Characteristics: small jaw, low-set ears, and a strawberry-shaped head.

Patau Syndrome

This person would suffer from serious eye, brain, & circulatory defects as well as cleft palate. 1:5000 live births. Children rarely live more than a few months.

Patau Syndrome

Jacob’s Syndrome XYY Tall Lean Acne prone Crooked eye Anger difficulties Some cognitive difficulties

Translocations

Prader-Willi Deletion on chromosome 15 - father imprinted

Angelman Deletion on chromosome 15 - mother imprinted

u Gene expression and inheritance depends on which parent passed on the gene. u Usually caused by different methylations of the DNA.

Imprints are "erased" in gamete producing cells and re-coded by the body according to its sex.

u Prader-Willi Syndrome and Angelman Syndrome u Both lack a small gene region from chromosome 15. u Male imprint: Prader-Willi  Female imprint: Angelman

Gene Mutations

Chromosome “M” -small circles of DNA located in mitochondria and plastids of plants. Mitochondria reproduces itself and it passes it DNA along to its daughter organelle only.

Chromosome “M” - All “M” Chromosomes come from mom

These genes help form proteins involved in respiration. Defects in these genes cause Mitochondrial diseases such as mitochodrial myopathy, diabetes, heart disease, Alzheimer’s disease. Cummulative mutations may role play in aging