Human Genetics

Chromosomal Disorders Nondisjunction – means “not coming apart”; when homologous chromosomes fail to separate, abnormal chromosome numbers may find their way into gametes Monosomy – missing one chromosome from a pair Trisomy – having three copies of a chromosome Ex] Trisomy 21 – extra chromosome-21

A karyotype displays a diploid number of chromosomes. Analyzing Karyotypes A karyotype displays a diploid number of chromosomes.

How Are Karyotypes Made?

Human Female Karyotype Human Karyotypes Human Female Karyotype Notation: 46, XX Autosomes Sex Chromosomes Notation: 46, XY

Karyotype Analysis Is this person a male or a female?   What condition does this person have? Trisomy 21 / Downs Syndrome What was it caused by? Nondisjunction  What notation would you use to characterize this patient’s karyotype? 47, XY, +21

Recognizing Disorders in Karyotypes

1. Jacob’s Syndrome

2. Turner’s Syndrome

3. Cri-Du-Chat

4. Klinefeleter’s Syndrome

5. XXX Syndrome

Trisomy 13: Patau’s Syndrome 6. Trisomy 13: Patau’s Syndrome

WARNING: You may not want to look at the next slide.

Trisomy 18: Edward’s Syndrome 7.

8. Trisomy 21: Down’s Syndrome