1. Chromosomal Mutations and Karyotypes

2. Chromosomes Humans have 46 chromosomes (diploid =2N)
2 of them are sex chromosomes (the last pair)
X and Y they determine what sex you are
XX = female
XY = male
44 of them are autosomes
they do not determine the sex of an individual.
they code for everything else

4. Chromosomes
 Males (Xy)
Females (XX) 

5. Differences among species
Each organism has a characteristic number of chromosomes
The number is constant with the species
Potatoes, plums, and chimpanzees all have 48 chromosomes

6. Differences among species
Oats, Raccoon Dogs, Rats, Wheat and Wolverines all have 42 chromosomes

7. Differences in Species
If multiple organisms can have the same number of chromosomes, why do they look so different?
The order of the DNA nucleotides found on their chromosomes determines an organism’s traits
The number of chromosomes does NOT determine intelligence
Some plants, for example can have over 100 chromosomes- this doesn’t mean they are more intelligent than an organism with 46 chromosomes

8. Karyotypes Female A karyotype is a picture of an organisms chromosomes
We can determine the sex of an organism as well as determine if it has mutations or nondisjunction
What is the sex of this organism?
Female

9. Karyotypes During mitosis, a picture of a cell is taken
The chromosomes are sorted into identical pairs and arranged from biggest to smallest
The 2 sex chromosomes are put at the end (pair 23)

11. Chromosomal Mutations
Mutations are changes made to an organism’s genetic material
These changes may be due to errors in DNA replication or during transcription, radiation, viruses and many other things
Mutations can occur within a specific gene (small scale) as well as to the chromosome as a whole (large scale)

12. Chromosomal Mutations
In protein synthesis we talked about SMALL scale mutations that involved changes in nucleotides
There are also LARGE scale mutations that can change entire segments of a chromosome
Deletions
Duplication
Inversion
Translocation

13. Chromosomal Mutations
Original Chromosome:
Deletion- when a piece of chromosome breaks off completely
Duplication- occurs when a segment of a chromosome is doubled 1 2 3 4 1 2 4 1 2 3 4

14. Chromosomal Mutations
Inversion- when a piece of DNA is removed from the chromosome, inverted/flipped and then placed back into the chromosome
Translocation- when the chromosome piece attaches to a nonhomologous chromosome 1 2 3 4 1 2 4 3 9

15. Chromosomal Mutations

17. Nondisjunction
Sometimes during meiosis, the chromosomes fail to separate correctly during anaphase I or anaphase II.
This is called nondisjunction

18. Nondisjunction
When a gamete has only 1 copy of the affected chromosome it is called monosomy
When the other gamete has 3 copies of one chromosome it is called trisomy

20. Nondisjunction Common Disorders
Klinefelter’s syndrome:
One to several extra sex chromosomes
Presence of a Y  male
Ex. XXY or XXXY

22. Turner’s syndrome: Only one sex chromosome
Absense of Y develops into female
Ex. XO

25. Downs Syndrome:
Autosomal
Trisomy 21
Most common birth defect

27. Patau Syndrome: Autosomal Trisomy 13 Rarely live past infancy
Neurological problems, polydactyl and facial defects

29. Edwards Syndrome: Autosomal Trisomy 18 30% of babies die by 1 month
Learning disabilities, congenital heart defects and malformations of digestive tract, urinary tract and genitals