201/Slides/Chromatin%2520Structure/&h=738&w=496&sz=160&tbnid=5v_1MWb3-tIJ:&tbnh=138&tbnw=93&start=5&prev=/images%3Fq%3Dchromatin%2Bpicture%26hl%3Den%26lr%3D%26ie%3DUTF-8%26sa%3DN

~zs9q/zsfig/chromatin.html&h=600&w=600&sz=77&tbnid=KQ3b5wmq68sJ:&tbnh=133&tbnw=133&start=9&prev=/images%3Fq%3Dchromatin%2Bpicture%26hl%3Den%26lr%3D%26ie%3DUTF-8%26sa%3DN Chromatin: Nucleosomes & Spacer DNA

Normal male karyotype at the 650 band level.

p q Chromosome Nomenclature

Chromosome Painting: SKY: Spectral Karyotyping

FISH: Williams Syndrome Fluorescent in situ hybridization

Down’s Syndrome

Erik Nichols and mother, St. Petersburg, FL

Erik Nichols, 21, and his sister, 17-year-old Lindsey, on their graduation from high school. (Saint Petersburg, FL)

James Webster and mother, Anne

Trisomy 21 Karyotype

Turner’s Syndrome

Short Stature (mean height < 5 feet) Failure to develop secondary sex characteristics Maldeveloped Ovaries (infertility; high risk of ovarian cancer) Variety of medical problems: cardiovascular, kidney, pancreas, skeletal, thyroid: MARKED VARIABLE EXPRESSIVITY Minor physical anomalies: webbed neck, low set ears, puffy hands and feet: MARKED VARIABLE EXPRESSIVITY Described in 1938 by Henry Turner Cause isolated in 1960 (loss of one/part of one sex chromosome) Normal intelligence Normal personality (problems of self-esteem and body image that may be associated with physical anomalies) Lowered spatial-visualization and quantitative reasoning ? Higher stereotypical feminine interests Background: Physical Symptoms: Behavioral Symptoms: Turner’s Syndrome

Turner’s Syndrome Karyotype

XYY Karyotype

Chromosomal Microdeletions: Prader-Willi and Angelman Syndromes

Paternal DNA Maternal DNA DeletedDeleted Prader-Willi Syndrome DeletedDeleted Angelman Syndrome Gene imprinted (turned off) Gene not imprinted (turned on)

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Usually caused by micro deletion in region q11-13 of the paternally transmitted chromosome 15. Several genes in this region are genomically imprinted in the maternal chromosome. Hence, if there is a paternal deletion in this region, there are no active genes. Short stature Mental retardation, learning difficulties Decreased muscle tone Hypogonadism Emotional lability Unregulated appetite or hyperphagia (  obesity) Cause: Symptoms: Prader-Willi Syndrome

Prader Willi Syndrome

Tanis, a girl with PWS

Normal development until 6-12 months, then delayed development Disproportionate head growth  microcephaly Abnormal EEG, seizures Marked deficit in language (no words to a few words) but better communication using nonvebral methods (e.g., facial expressions) Motoric problems (balance problems, ataxia of gait, hypermotoric actions) Attention problems (short attention span) Emotional exuberance (frequent laughter, smiling) Symptoms: Angelman Syndrome Cause: Microdeletion of region q11-13 of chromosome 15 that deletes a gene(s) that is paternally imprinted.

Angelman Syndrome

Angelman Syndrome