Selective Breeding

Have you ever watched a dog show? Many different breeds are presented. Judges look for the specific traits each type of dog should have.

Think about this. Why are there so many different breeds of dogs? How did some dogs get their unique traits?

Dogs, dogs, and more dogs

Dogs, dogs, and more dogs

Dogs, dogs, and more dogs

Dogs, dogs, and more dogs

Dogs, dogs, and more dogs

Dogs, dogs, and more dogs

Dogs, dogs, and more dogs

Dogs, dogs, and more dogs

Dogs, dogs, and more dogs

Dogs, dogs, and more dogs

Dogs, dogs, and…

the DAWG!

Selective Breeding Humans have used genetic patterns that occur naturally in dogs to pass on desired traits to the next generation. This is called selective breeding. Selective breeding has been used to produce faster race horses, new varieties of plants, etc.

Selective Breeding Selective breeding has been used to produce faster race horses, new varieties of plants, etc. This is what Gregor Mendel did with pea plants. He chose which plants would reproduce with other plants.

Inbreeding This type of selective breeding is used to maintain, or keep, certain traits in offspring. Similar individuals are crossed in order to increase the chance of the offspring having the traits of their parents.

Inbreeding This sometimes causes problems because it increases the chance that an offspring will inherit two recessive alleles that may cause a genetic defect.

Inbreeding For example, some German shepherds and Labrador retrievers have joint problems because of too much inbreeding. Dachshunds may have heart problems.

Hybridization This is where two individuals with different traits are crossed in hopes of getting the best traits from both parents.

Hybridization Remember: hybrid is another way to say heterozygous, or different. It means different or mixed.

Hybridization Suppose there was a type of corn that was very drought resistant and another type of corn that had a great flavor. What would you hope to get by crossing those two varieties?

Examples of Hybrid Animals Liger (see article)

Examples of Hybrid Animals Zebra + Donkey = Zedonk

Examples of Hybrid Animals Donkey + horse= Mule

Genetic Engineering This is where scientists take bits of genetic material from one organism and insert it into another.

Genetic Engineering This is where scientists take bits of genetic material from one organism and insert it into another. They hope to someday use this technique to cure genetic disorders. YouTube - Genetic Engineering Animation

Genetic Disorders Down Syndrome

Genetic Disorders Sickle Cell

Genetic Disorders Albinism

Genetic Disorders Cystic Fibrosis

Cloning This involves using the genetic information from one organism to produce an exact copy of that same organism. A sheep named Dolly was the first mammal cloned.

Dolly

Ethics Do you think scientists should be experimenting with and manipulating genes?

Cloning and genetic engineering do not occur naturally Cloning and genetic engineering do not occur naturally. They happen in laboratories.