Karyotypes Objective: 6H - describe how techniques such as DNA fingerprinting, genetic modifications, and chromosomal analysis are used to study the genomes of organisms

Human Female Karyotype Karyotypes Human Female Karyotype Autosomes Sex Chromosomes Autosomes Sex Chromosomes Notation: 46,XY Notation: 46,XX Diagnosis: Normal male Diagnosis: Normal female

Analyzing Karyotypes A karyotype displays a diploid number of chromosomes.

Chromosomal disorders   Nondisjunction – means “not coming apart”; - when homologous chromosomes fail to separate, abnormal chromosome numbers may find their way into gametes

Exp. Trisomy 18 – extra chromosome 18   Monosomy – missing one chromosome from a pair Exp. Monosomy 23 – missing a sex chromosome Notation: 45,X0 Trisomy – having three copies of a chromosome Exp. Trisomy 18 – extra chromosome 18 Notation: 47,XX,+18 or 47,XY,+18

No Nondisjunction male 47, XY, +21 Trisomy 21 Does this person have a normal # of chromosomes? What was it caused by? Is this person a male or a female? What notation would you use to characterize this patient’s karyotype? What condition does this person have?      No Nondisjunction male 47, XY, +21 Trisomy 21 (Down Syndrome)

Common Non-disjunction Disorders Turner’s Syndrome – Monosomy 23 Notation: 45,X0 Kleinfelter’s Syndrome – Trisomy 23 Notation: 47,XXY Down’s Syndrome – Trisomy 21 Notation: 47,XX,+21 or 47,XY,+21 Edward’s Syndrome – Trisomy 18 Notation: 47,XX,+18 or 47,XY,+18 Patau Syndrome – Trisomy 13 Notation: 47,XX,+13 or 47,XY,+13

Amniocentesis a procedure a pregnant woman can have in order to detect some genetics disorders…such as non-disjunction. Amniotic fluid withdrawn

How are Karyotypes made? Add chemical to stimulate mitosis Add chemical to stop mitosis in metaphase Eventually, stain chromosomes Identify & photograph chromosomes Cut out chromosomes & arrange into karyotype

Practice: What is the sex of this patient? What notation would you give this patient? What diagnosis would you give this patient? Female (Why? No Y chromosome) 45, XO Monosomy 23

Now, you are going to pretend to be a geneticist and diagnose patients by looking at karyotypes. Karyotype Activity Due Today