Karyotypes and Karyotyping

1. Karyotypes and Karyotyping

2. What Are They? A karyotype is “a visual representation of an individual’s chromosomes arranged in a specific way.” Karyotyping chromosomes involves classifying and organizing them according to the arrangement, number, size, shape, or other characteristics of the chromosomes. These pictures of an individual’s chromosomes allow scientists/doctors to identify characteristics of a person such as gender and genetic disorders, among other things.

3. How Scientists Read Chromosomes? • Size. This is the easiest way to tell two different chromosomes apart. • Banding pattern. The size and location of Giemsa bands on chromosomes make each chromosome pair unique. • Centromere position. Centromeres are regions in chromosomes that appear as a constriction. They have a special role in the separation of chromosomes into daughter cells during mitosis cell division (mitosis and meiosis). To "read" a set of human chromosomes, scientists first use three key features to identify their similarities and differences: Image taken from: http://learn.genetics.utah.edu/content/begin/traits/scientists/ Using these key features, scientists match up the 23 pairs – one set from the mother and one set from the father.

4. Typical Female Karyotype 46 Total Chromosomes Image taken from: http://worms.zoology.wisc.edu/zooweb/Phelps/karyotype.html

5. Typical Male Karyotype 46 Total Chromosomes Image taken from: http://worms.zoology.wisc.edu/zooweb/Phelps/karyotype.html

6. Monosomy X - Turner Syndrome - Karyotype 45 Total Chromosomes One “X” Chromosome Image taken from: http://worms.zoology.wisc.edu/zooweb/Phelps/karyotype.html

7. Trisomy 21- Down’s Syndrome - Karyotype 47 Total Chromosomes Three Chromosomes at the 21st Pair Image taken from: http://worms.zoology.wisc.edu/zooweb/Phelps/karyotype.html

8. XYY Karyotype 47 Total Chromosomes One “X” and Two “Y” Chromosomes Image taken from: http://worms.zoology.wisc.edu/zooweb/Phelps/karyotype.html