1. Human Genetics

2. Multiple Alleles
There are more than two possible genes that can be inherited for a trait.
Examples
Flower color
Blood type

3. Sex-linked Traits
Trait for which the gene is located on one of the sex chromosomes.
XHXH ~ female, normal
XHXh ~ female, normal carrier
XhXh ~ female, hemophiliac
XHY ~ male, normal
XhY ~ male, hemophiliac

4. Pedigrees
A family tree that shows how a particular trait is passed from parents to offspring.
Be able to read and interpret

5. Pedigree of a Sex-linked Trait
Colorblindness is sex-linked.
Blue box is colorblind
White box is normal vision with two normal genes.
Half blue/half white is a carrier with normal vision, but one abnormal gene.

7. Karyotypes
Process in which cells undergoing mitosis are crushed, and their chromosomes paired up. This can reveal abnormalities as seen below.
Female – 2 X chromosomes

8. Nondisjunction
The failure of chromosomes to separate during anaphase I or II of meiosis.
Can result in too many chromosomes (Down Syndrome) or not enough (Turner Syndrome)

9. Autosomal Dominant Diseases
If the abnormal gene is present, the person has the disease
Huntington’s Disease

10. Huntington’s Disease Chromosome 4 HH or Hh Nerve cells degenerate
Symptoms include: mood swings, irritability, loss of memory, and uncontrolled movements
People of western European descent

11. Autosomal Recessive disease
Must have 2 abnormal forms of the gene for the disease to be present
Cystic Fibrosis
Tay Sachs
PKU (Phenylketonuria)
Sickle Cell Anemia

12. Cystic Fibrosis Chromosome 7 cc
Causes think, sticky mucus to build up in the lungs, digestive tract, and other areas of the body
Mainly Caucasians

13. Tay Sachs Chromosome 15 tt
Causes a buildup of a chemical on the nerve cells
Babies lose or fail to gain motor and mental skills
Paralysis usually occurs
Death at an early age
Jews of eastern European descent and French-Canadians

14. PKU
Chromosome 12 pp
Born without the ability to break down phenylalanine
Smaller than normal head, epilepsy, and mental retardation may occur when undiagnosed
Caucasians and east Asians

15. Sickle Cell Anemia Chromosome 11 ss
Red blood cells form an abnormal crescent shape
Pain; spleen, lung, and heart damage, and anemia
People of African
descent

16. Sex-linked Diseases
Gene for the disease is carried on the sex-chromosome
Colorblindness
Hemophilia

17. Colorblindness Carried on the X chromosome XbXb or XbY
Cannot distinguish between colors
Affects all races and ethnic groups

18. Hemophilia Carried on the X chromosome XhXh or XhY
Blood does not clot well because missing the gene that codes for a blood clotting protein
Affects all races and ethnic groups

19. Chromosomal Aneuploidy Diseases
A disease caused by an abnormal number of chromosomes
Down Syndrome
Turner’s syndrome
Kleinfelter’s syndrome
XYY Male

20. Down’s Syndrome Autosomal anueploidy Trisomy (three chromosomes at 21)
Mental retardation, upward slant to the eyes, decreased muscle tone, and a variation of other symptoms

21. Turner’s Syndrome Sex chromosome anueploidy Monosomy
Alters development in females; shorter than average, infertile, extra skin on the neck, skeletal abnormalities, heart defects, and kidney problems

22. Kleinfelter’s Syndrome
Sex chromosome anueploidy
Trisomy (XXY)
Armpit and facial hair, enlarged breasts, tall stature, and abnormal body proportions
Increased possibility of learning disorders

23. XYY Male Sex chromosome anueploidy Trisomy (XYY)
Increased risk of learning disabilities, delayed speech and language skills