1. Human Genetics
Human Genetics

2. Human Chromosomes
Karyotype = picture of chromosomes arranged in pairs & organized by size
Humans have 46 chromosomes
of these are sex chromosomes
             XX = female XY = male
the other 44 chromosomes are known as autosomes

4. Down Syndrome
Trisomy 21

7. Edward Syndrome - caused by an extra chromosome 18 (trisomy 18)
Median life expectancy is 4 days. However, about 5-10% survive beyond one year

8. NONDISJUNCTION
Failure of chromosomes to separate in meiosis – results in an egg (sperm) with too many or too few
Down Syndrome (extra #21)
Klinefelter Syndrome (XXY)
Turner Syndrome (XO)
Supermale (XYY)

9. Trisomy – 3 chromosomes Monosomy – 1 chromosome

12. Check your understanding
A picture of a person's chromosomes is called a _____.
In this pictures, chromosomes are arranged in  pairs according to their ___________.
Humans have ______ pairs of chromosomes.
The last set of chromosomes is the _____ chromosomes.
Males have what sex chromosomes?  ______
A person who has an extra chromosome #21 has what disorder? __________
If a person has XXY for sex chromosomes, he has what disorder? _________________
As a woman gets _______, her risk for having a child with down syndrome increases.
A human has 2 sex chromosomes, the other 44 chromosomes are called ______________.
When chromosomes fail to separate during meiosis,  ___________ has occurred.

13. Human Traits To study inheritance, biologists use pedigree charts
Shows relationships within a family

15. Not all human traits can be traced back to a single gene!
Many traits are strongly influenced by environmental factors
(eg: height, weight, personality)

16. Human Genome Our complete set of genetic info
Includes thousands of genes
Base sequences of many genes identified

17. BLOOD TYPES
Genes controlling blood types were 1st genes to be identified
ABO & Rh blood groups ( + and - )

18. ABO Blood Group Multiple Allele Trait
Controlled by 3 alleles:  A, B, O
A and B are codominant
O is recessive to both A and B
The blood type is the phenotype

19. IBIB, IBIi IAIB, IAIA, IAIi (use superscript) Type A Type B codominant
Genotype
Blood Type
IAIA, IAIi (use superscript)
Type A
IBIB, IBIi
Type B
IAIB,
codominant
Type AB
(universal recipient)
IiIi recessive
Type O (universal donor)

20. Blood Types Practice
Mum has type A blood (genotype AO); Dad has type AB blood. What blood types are possible among their children?
Mum has type B blood (genotype BO); Dad has type O blood. What blood types are possible among their children?

21. Human Genetic Disorders
Phenylketonuria (PKU)
Tay – Sachs disease
Albinism                          * all recessive

22. Other animals can be albino too..

23. Remember Sickle-Cell Disease
codominant (AA, Aa, aa )
heterozygous is resistant to malaria

24. Achondroplasia (dwarfism)
Huntington’s disease
* Both dominant

25. Check your understanding
1.  Achondroplasia is another name for ____________
2.  What are the four possible blood types? _______
3.  Is albinism dominant or recessive? _________
4.  If two people are both heterozygous for sickle cell trait, what is the chance they they will have a child with sickle cell disease?
5.  If a person with type A blood is married to person with type O blood, what blood types are possible in their children?
6.  The human _______ describes all the genes found in humans.
7.  What type of chart is used to study a trait in a family? __