Karyotypes An Organized Picture of Your Chromosomes Creating

Karyotypes An Organized Picture of Your Chromosomes!!

Creating a Karyotype • During cell division (metaphase), stain the chromosomes and then take a picture. • Magnify the picture to make the chromosomes larger. • Cut out and place in order pair 1 -23 from largest to smallest.

How to determine the sex of the individual. • Human Karyotype has 23 pairs of chromosomes. • Pair 23 is the sex chromosomes – If the 23 rd pair looks identical it is XX, if they look different it is XY. • No matter how many chromosomes you see, if there is a shorter chromosome in pr 23 it is male.

Human Karyotype 1 – 22 Autosomal Chromosomes Pair 23 – Sex Chromosomes Male – XY Female - XX Absence of Presence of the Y chromosome determines the sex of the individual

Female Notice the Y spot is there but there is nothing in it.

Male No matter the number of X chromosomes, the presence of a Y makes it a male

What is the point? • Use this picture to diagnose chromosomal disorders such as Down Syndrome – Trisomy 21 Turner’s Syndrome – X Klinefelter’s Syndrome – XXY How do chromosomal disorders happen? Nondisjunction – “Not coming apart” When this happens abnormal numbers of chromosomes may find their way into gametes.

Karyotypes Show Chromosomal Mutations • Deletion – Loss of all or part of chromosome • Duplication – Extra portion of chromosome • Inversion – Chromosome is oriented in the reverse direction • Translocation – Part of a chromosome attaches to another nonhomologous chromosome

Deletion Karyotype

Duplication Karyotype

Translocation Karyotype

• http: //www. biology. arizona. edu/human_bio /activities/karyotyping/Karyotyping. html