E N D
1. The Human Genome Chapter 14
2. Human Heredity Human chromosomes
Karyotype – a picture of chromosomes arranged in pairs
3. Human Heredity
4. Human Heredity Human body
46 chromosomes
Haploid sperm cell with 23 chromosomes
Haploid egg cell with 23 chromosomes
They form a diploid zygote or fertilized egg cell with 46 chromosomes
5. Human Heredity Sex chromosomes
2 of the 46 chromosomes
Determine the sex of that person
Females have X and X or XX chromosomes
Males have X and Y or XY chromosomes
6. Human Heredity Autosomes (Autosomal Chromosomes)
The other 44 chromosomes found in all body cells
These are the chromosomes separate from the sex cells
Typically numbered on a karyotype
7. Human Heredity Human traits
Pedigree chart – Shows the relationship within a family
Shows how traits may be passed through generations
9. Human Heredity Human genes
Blood group genes
Rh blood groups
Positive and negative
Rh+ is dominant
ABO blood groups
IA, I B, and i
IA and I B are codominant
10. Human Heredity Recessive alleles
Genetic disorders usually are not discovered until seen in the environment
Dominant alleles
Anyone having carrying an allele will have the disorder
Codominant alleles
11. Human Heredity From gene to molecule
Cystic fibrosis
Common in people from northern Europe
Serious digestive and breathing problems
Caused by the deletion of just one amino acid
12. Human Heredity Sickle cell disease
Blood cells doughnut or comma shaped
Heterozygous people don’t contract malaria
Humans with all sickle celled blood can die
Why do so many African Americans have sickle celled blood?
13. 14-2 Human Chromosomes Human genes and chromosomes
One cell has 6 billion base pairs or A,C,T,& G
46 Chromosomes are found in every diploid human cell
14. 14-2 Human Chromosomes Only 2% of all DNA is used for genes or transcribed into RNA
Average genes are 3,000 base pairs
Largest gene is 2 million base pairs
15. 14-2 Human Chromosomes Chromosomes 21 and 22 are the smallest
22 has 545 genes (43 million base pairs)
21 has 225 genes (21 million base pairs)
Lou Gehrig’s Disease or Amyotrophic Lateral Sclerosis(ALS)
16. 14-2 Human Chromosomes Sex-linked genes – genes located on the sex chromosomes
Colorblindness
Red-green colorblindness
1 in 10 males
1 in 100 females
Why do more males have colorblindness?
18. 14-2 Human Chromosomes Hemophilia
Blood does not clot properly
Is determined by two genes on the X-chromosome
1 in 10,000 males
Ryan White
19. 14-2 Human Chromosomes Duchenne Muscular Dystrophy
Progressive weakening and loss of skeletal muscle
1 in 3,000 males
Caused by a defective gene that codes for a protein in muscles
20. 14-2 Human Chromosomes X-chromosome inactivation
Barr body – dense area in a nucleus where the inactivated X chromosome is located
Each cell controls which X chromosome is turned off
Calico cat
21. 14-2 Human Chromosomes Chromosomal Disorders
Nondisjunction – error in which homologous chromosomes fail to separate
22. 14-2 Human Chromosomes Down syndrome
Caused by trisomy or three copies of chromosome 21(Trisomy 21)
1 in 800 babies
This is a nondisjunction condition
23. 14-2 Human Chromosomes Sex chromosome disorders
Turner’s syndrome
Females (45,X)
Sterile
No sex organs
Klinefelter’s syndrome
Males (47, XXY)
Sterile
24. 14-3 Human Molecular Genetics Human DNA analysis
Search the human genome using sequences of DNA bases
25. 14-3 Human Molecular Genetics Testing for alleles
Use labeled DNA probes
Search for changes in restriction enzymes
Test lengths of DNA strands
26. 14-3 Human Molecular Genetics DNA fingerprinting
No two humans are exactly alike
Analyze and compare low function DNA segments
27. 14-3 Human Molecular Genetics The Human Genome Project
An ongoing effort to analyze the human sequence
Finished in 2000
28. 14-3 Human Molecular Genetics Rapid sequencing
Identify separated regions of DNA
Use these areas as markers
Shotgun sequencing
29. 14-3 Human Molecular Genetics Searching for genes
Find DNA sequences known to be promoters
This is the start of a gene
30. 14-3 Human Molecular Genetics A breakthrough for everyone
Public access to Human genome project
31. 14-3 Human Molecular Genetics Gene therapy
Changing the gene that causes a genetic disorder
Use viruses to infect cells with good gene
1999 - First person cured of genetic disorder
32. 14-3 Human Molecular Genetics Ethical issues in human genetics
Should we use genetics to make people better?