1. Karyotyping

2. Karyotyping is when a scientist cracks open a nucleus, removes all the chromosomes.
The scientist then lays out all the individuals chromosomes and pairs the homologous pairs in order to learn something about the individuals genetics
So lets first discuss what a chromosome is and what we can learn from them

3. CHROMOSOMES ARE IN NUCLEUS

4. CHROMSOMES ARE TIGHTLY WRAPPED DNA

5. A GENE IS A SEGMENT OF DNA THAT CODES FOR A PARTICULAR TRAIT

6. REMOVED FROM NUCLEUS

7. STAINING

8. CHROMOSOMES LOOK LIKE Xs if you find them in when the DNA is duplicated (Interphase S phase-Metaphase)

9. The rest of the time the chromosomes are singular poles
This is how they will be shown the majority of the time

10. Human Chromosomes Humans have 46 chromosomes normally.
22 autosomes (2 of each) and
2 “sex” chromosomes
“Sex Assigned At Birth”- male or female designation made by hospital either by karyotyping or by physical anatomy at birth
Female: X___
Male: X__

11. Human Chromosomes Humans have 46 chromosomes normally.
22 autosomes (2 of each) and
2 “sex” chromosomes
“Sex Assigned At Birth”- male or female designation made by hospital either by karyotyping or by physical anatomy at birth
Female: XX
Male: XY

12. Karyotype
Karyotype- when scientists look at chromosomes and arrange them, and analyze them.

13. Karyotype Arranged by size Arranged by position of centromere
First arrange normal chromosomes
Try to arrange anything irregular

14. Staining chromosomes
Stain Giemsa Staining stains the A and T rich portion of DNA dark.
Banding patterns depend on genetic code
Banding patterns unique to certain chromosomes

15. 23 homologous pairs 46 chromosomes
Normal Karyotype
23 homologous pairs
46 chromosomes

16. What are the sex chromosomes ?

17. X and Y

18. What is determined by sex chromosomes?
SOME TRAITS: sex chromosomes do not carry an identical complement of genetic information. The X chromosome, being larger, carries many more genes than does the Y. Traits controlled by genes found only on the X chromosome are said to be sex-linked. Recessive sex-linked traits, such as hemophilia and red–green color blindness, occur far more frequently in men than in women. This is because the male who inherits the recessive allele on his X chromosome has no allele on his Y chromosome to counteract its effects.
Controls Hormone Production

19. Chromosomal notation:
46,XY(chromosomally normal female)
46,XX(chromosomally normal male)
47,XX,+21 ABNORMAL EXTRA 21 what’s the disease?

20. Down Syndrome
3 chromosomes
(21st pair)

21. Down Syndrome Traits
mental retardation
epicanthal folds over eyes
flattened bridge of the nose

22. When Meiosis Fails

23. produces 4 genetically different sex cells but same chromosome number
Normal Meiosis:
produces 4 genetically different sex cells but same chromosome number

24. An uneven splitting of the chromosomes during meiosis
Nondisjunction
An uneven splitting of the chromosomes during meiosis

25. Nondisjuction Animation

26. Down Syndrome Karyotype
3 chromosomes
(21st pair)

27. Down Syndrome Traits
mental retardation
epicanthal folds over eyes
flattened bridge of the nose

28. Nondisjunction in Sex Chromosomes

29. Turner Syndrome: Missing X

30. Turner Syndrome Symptoms
short stature
sterile
webbed neck
skeletal disorders

31. XYY Syndrome 5-10 born each day in USA
Falsely called “superman” or “criminal” syndrome.
5-10 born each day in USA

32. XYY Symptoms taller more hairy heavy facial features
delays in learning & language
violent tendencies ????

34. Klinefelter Syndrome: XXY

35. Klinefelter Symptoms underdeveloped male traits mammary development
learning disabilities
language delays
infertility