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

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

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

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

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)

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

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

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

Hemophilia Chart

Royal Family Pedigree

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

Achondroplasia

Cystic Fibrosis

Tay-Sachs Disease

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

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

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

Identical twins

Biotechnology