1. Karyotype Notes

2. What each of the human chromosomes look like

3. Karyotype: A photomicrograph of chromosomes arranged according to a standard classification

4. In other words…
Chromosomes are digitally arranged so that they are matched with their homologue or “partner” chromosome.
Homologue chromosomes are the same size, shape, and carry the same genes, and one is inherited from each parent.
They are numbered according to size.

5. Sex determination with karyotype
This karyotype has 23 exact pairs, which means the person is female.
Note that #23 chromosomes are both X.

6. Normal human male Note that #23 chromosomes are X and Y.
Notice the size of the Y chromosome.
It is much smaller then the X

7. Is this person female or male?

8. If there are chromosomal number abnormalities, how do they form?
Meiosis: the process of creating sperm or egg from a diploid cell
If there is a mistake when chromosomes are separating, then the resulting sperm or egg will have too many or too few chromosomes – this is called nondisjunction

9. Nondisjunction
Notice the gametes have an uneven distribution of chromatids

10. Trisomy 21 Abnormality shown in karyotype
Note that there are three copies of #21 chromosome.
This person has Down Syndrome.

12. Correlation between mother’s age and Trisomy 21 incidence

13. Monosomy X Abnormality shown in karyotype
Note this person only has 1 copy of the X chromosome.
This female has Turner’s syndrome.

15. XXY Male (Extra X)
Notice that this person has an extra X chromosome. This is called Klinefelters. They would be considered a male even though they 2 X chromosomes