1. Chapter 8: Genetic Changes
Mutations- any change in an organism’s genetic material
This can occur as a single base pair change or it can involve an entire chromosome
Mutations are almost always harmful, although the harmful effects may not always be apparent
EX. The skin of the Red Delicious apple became green as a result of a mutation forming the Golden Delicious apple
A mutation that causes death is called a Lethal Mutation

2. Gene Mutations A GENE MUTATION is the most common type of mutation
This is a permanent change in DNA.
It occurs when there is a change in the sequence of bases in the segment of DNA that makes up a gene.
It can range from a single to a large segment of a chromosome.
The effect of a mutation can differ greatly

3. Gene Mutation: Effects
No effect- If a gene for eye color mutates in a finger cell, or any other cell other than an eye cell, the organism will not experience any change
Minor effects- a freckle or spot
Major effect- skin cancer

4. Somatic and Germ Mutations
Somatic mutation- mutations that occur in body cells.
-These are not passed on to future generations, so they do not affect the children
Germ Mutations- mutations that occur in the gametes (or reproductive cells)
Germ Mutations are passed down
Most are recessive so the offspring must have 2 genes to express the mutated gene

5. Chromosomal Changes
Chromosomal change- this involves a change in the number of chromosomes, the number or the location of genes on a chromosome
A chromosomal change, unlike other mutations, does not directly involve the formation of proteins, but can still change an organisms expected traits
Like gene mutations these may be somatic or occur in the gamete (germ)

6. Chromosomal Changes Chromosomal changes generally occur in sets
Diploid- having 2 sets for each gene, chromosomes
Humans have 2 sets of 23 chromosomes making 46 total
Ploidy- changes in the number of sets of chromosomes

7. Chromosomal Changes: Ploidy
Seedless watermelons-have 3 instead of 2 sets of chromosomes
Down Syndrome- a human disorder caused by a change in ploidy
There is a 3rd chromosome, one extra, on the 21st (or 22nd) chromosome
47 instead of 46 chromosomes

8. Chromosomal Changes: Hemophilia
Hemophilia is a genetic disorder.
It is called the “bleeder’s disorder” because it does not allow a person’s blood to clot, leaving a person susceptible to bleeding to death.
It occurs as a sex-linked gene, meaning it is carried on the X chromosome
Hemophiliacs are rare, 1 in 10,000 males
Queen Victoria and her royal family were affected by this disease

9. Hemophilia Chart

10. Royal Family Pedigree

12. Inherited Human Disorders
Hemophilia- sex-linked
Duchenne muscular dystrophy- sex-linked
Red-green colorblindness- sex-linked
Tay-Sachs disease- recessive, chromosome 15
Cystic Fibrosis- recessive, chromosome 7
Malignant hyperthermia- Usually dominant
Achondroplasia- Dominant, chromosome 4

13. Achondroplasia

14. Cystic Fibrosis

15. Tay-Sachs Disease

16. Applied Genetics
Selective breeding- man chooses organisms with desirable traits and breeds them hoping that the offspring will have those traits
Inbreeding- mating of an organism with its close relatives, or in plants, with itself
Cross-breeding- method used to produce organisms with desirable traits (hybridization)
Breeding individuals from different varieties to obtain the traits of both parents

17. Cross Breeding
Santa Gertrudis cattle is a cross between the Brahman and a Shorthorn

18. Biotechnology Genetic engineering Cloning
Natural clones= identical twins
Human genome project

19. Identical twins

20. Biotechnology