Presentation on theme: "Nondisjuncti on Homologous pairs do not move apart during Meiosis."— Presentation transcript:
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
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???)
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.
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.
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
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