1. Human Heredity- Karyotyping and Geneics Disoders

2. What makes us human?
To analyze chromosomes, cell biologist photograph cells in mitosis, when the chromosomes are fully condensed and easy to see.
Biologists then cut out the chromosomes and group them together in pairs.
A picture of chromosomes arranged this way is known as a KARYOTYPE.

3. Human Karyotype

4. What Can Our Chromosomes Tell Us?
They can tell us everything from the likelihood that an unborn baby will have a genetic disorder to whether a person will be male or female.
Scientists often analyze chromosomes in prenatal testing and in diagnosing specific diseases.

5. Making a Karyotype
A karyotype is an organized profile of a person's chromosomes.
Chromosomes are arranged and numbered by size, from largest to smallest.
This arrangement helps scientists quickly identify chromosomal alterations that may result in a genetic disorder.

6. Using Karyotypes to Predict Genetic Disorders
A normal human karyotype has 46 chromosomes: 22 pairs of autosomes and 2 sex chromosomes.

7. Karyotype of a Normal male
Chromosome Number
Homologous chromosomes
Dark bands
= Genes
Autosomal chromosomes
= non sex determining chromosomes, same shaped homologous
Sex chromosomes

8. Sex chromosomes:
X = female, Y = male
X/Y = male
X/X = female

10. Chromosomal disorders
What if you have extra chromosome?
What if you are missing a chromosome?
Chromosomal disorders usually:
Increase chance of having disorders, such as mental disability, sterility, and decrease life expectancy.

11. Chromosome 21 trisomy  Down syndrome
Is anything wrong?
Male
Chromosome 21 trisomy  Down syndrome

12. Trisomy 21( extra on the 21st)- Down Syndrome
• Redundant neck fold/flat occipital (back of the head)
• Low set ears
• Protruding/large tongue
Wide space between 1st & 2nd toes

13. Trisomy 13 (47,XY,+13) – Cleft Lip

14. Cleft Lip- a split or indentation in the lip of a newborn baby.

15. Is anything wrong? X
Turner’s syndrome

17. Is anything wrong?
XXY
Klinefelter’s syndrome

18. Color Blindness

19. Colorblindness
3 human genes associated with color vision are located on the X chromosome.
Because males have one X chromosome, all the genes will be expressed, even if they are recessive. **Increase in Males!