Karyotype: A display of the chromosome of an individual Matched by homologous pairs Chapter 11.3

Karyotype Photograph of chromosomes of a normal male Cell is stopped in the middle of division (metaphase)

Karyotype of Normal Male Shows all 23 chromosomes in order from largest to smallest. Chromosome 23 are the sex chromosomes, this is a male because it is XY

Karyotype of Normal Female Female = XX

Diagram of female homologous chromosomes

Telomeres Chromosomes end in a protective cap called telomeres. Consist of DNA associated with proteins Serves protective function for structure of chromosome Might be involved in aging and cancer.

Non-Disjunction (failure of homologous chromosomes to separate properly during meiosis)

Chromosomal Disorders: Deletion TurnerSyndrome Monosomy X Students should know types of chromosomal disorders (like deletions and additions) but do not need to know individual syndromes Only one X chromosome = monosomy X, also known as Turner Syndrome. This would be a female (no Y chromosome), may be lacking in some female characteristics (Incomplete puberty, may not menstruate, infertile, short height)

Cri du Chat - Cry of the Cat: Partial Deletion of #5 Cry sounds like a cat (high-pitched), causes mental retardation

Chromosomal Additions Patau's Syndrome: Trisomy of Chromosome 13 3 copies of chromosome 13, child will not develop normally, defects of the heart, kidney, and nervous system

Edward's Syndrome: Trisomy of Chromosome 18 Some mental delay and facial deformities

Down Syndrome: Trisomy 21 Most common human genetic abnormality, causes mental delay, inhibits physical growth, distinctive facial features

Klinefelder Syndrome: Trisomy 23rd pair XXY Male (have Y chromosome) but may express some female features – low levels of testosterone, sparse facial hair, etc.

Trisomy 23: XYY Jacob’s syndrome – may have some learning problems and delayed cognitive abilities. Extra testosterone may cause prevalence of male characteristics (height, facial hair, etc.)