NondisjuncNondisjunctiontionHomologous Homologous pairs do pairs do not move not move apart apart during during MeiosisMeiosis

NondisjuncNondisjunctiontionaneuploidyaneuploidy- - abnormal abnormal numbernumber

--2n + 12n + 1 ex. ex.

Down’sDown’s trisomictrisomic

- - 2n - 1 2n - 1 ex. ex.

Turner’sTurner’s monosomicmonosomic

Turner’s Syndrome

trisomic

monosomic

Trisomy 21

Trisomic 2n + 1

Down Syndrome /

Trisomy 21

Turner Syndrome

Xmonosomic 2n

- 1

Klinefelter’s Syndrome

2N + 1 (2N + 2, 2N + 3)GenotypeGenotype: XXY (XXXY, XXXXY)PhenotypePhenotype: male, but sexual development may be poor. Often taller than average, mental development fine (XXY), usually sterile.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

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

Edward’s Syndrome

Edward’s Syndrome

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

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 XYYTall

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

Gene expression and inheritance

depends on which parent passed on

the gene.

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.

Prader-Willi Syndrome and Angelman SyndromeBoth lack a small gene region from chromosome 15.

Male imprint: Prader-WilliFemale 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