15.1 SELECTIVE BREEDING(Hybridization vs. Inbreeding;

biotechnology)

15.1 SELECTIVE BREEDING(Hybridization vs. Inbreeding;

biotechnology)

• Hunters in the 1800’s needed a hunting dog that was big, strong, fast, and aggressive

• However, no dog like this existed at that time

• They knew of two species of dogs, each with some of the desired qualities

• Can they somehow combine the two into one?

Big and strong, but lacked speed and aggression

Fast and aggressive, but lacked strength

Big, strong, fast, and aggressive

Why use selective breeding?

• Humans use selective breeding, which takes advantage of naturally occurring genetic variation, to pass wanted traits on to the next generation of organisms

• What ways can humans selectively breed plants or animals?

2 Types of Selective BreedingHybridization

• Crossing dissimilar individuals to bring together the best of both worlds

• American botanist Luther Burbank selectively bred 800 plants, called varieties

• Many varieties can be found in your supermarket!

• Bred for size, disease resistance, flowering, taste, color and a variety of other reasons based on preference

Inbreeding• Crossing breeds of

individuals with similar characteristics

• Maintains traits of that breed (purebreds)

• Risky – increases chance for mutation since individuals are very genetically similar to each other

Hybridization

• Hybridization occurs in both plants and animals

• Creating hybrid plants is different than creating hybrid animals

• Animals can be sterile if their chromosome number is odd, or if there are too many mutations that occur when they breed naturally (rarely occurs in the wild)

• Plants can be bred easily by gardeners or botanists

• Many crops today are hybrids (can sometimes occur naturally in the wild)

Genetically-Engineered Hybrid Plants

• You have probably eaten many GE plants without realizing it. Examples include:

• Seedless grapes/ watermelons• Bananas, which commonly have

polyploidy (extra sets of chromosomes – stronger, bigger)

• Corn – modern corn wasselectively bred from teosinte at least 6,000 years ago

Can you guess these hybrid fruits?

• Limequats– Lime x Kumquat

• Tangelo– Tangerine x Pomelo

Hybridization• Hybridized animals are called hybrids• Can you identify these hybrids?

http://www.youtube.com/watch?v=1zOWYj59BXI

• WEBSITE: http://www.dogbreedinfo.com/hybriddogs.htm

• List of Hybrid Dogs (Designer Dogs) (Boutique Dogs)

• The word ”hybrid,” when referring to genetics means, “the offspring of genetically dissimilar parents or stock, especially the offspring produced by breeding plants or animals of different varieties, species, or races.” In general, the word means, “something of mixed origin or composition.” Hybrid dogs, or designer dogs as some call them, are becoming quite popular. Below is a list of the most popular hybrid dogs. The best way to determine the traits of a mixed breed is to look up all breeds in the cross and know you can get any combination of any of the characteristics found in all breeds. The Dog Breed Info Center® does not attempt to interpret the temperaments of each individual hybrid mix because the differences in the dogs, even within the same litter, can vary greatly. If you do not feel the temperament of one of the purebreds in the mix is suited for your lifestyle, then that hybrid dog is not for you. Do not take a gamble that the puppy or dog will turn out like the other breed in the mix. Choosing a dog simply for its looks is a foolish way to choose a dog. Read the article on Designer Dogs for more info on these mixed breeds.

• Please Note: A hybrid dog is not a BREED; it is a hybrid, which means it is a mix of more than one purebred dog.

• Scientifically speaking, the term "hybrid” is incorrect as all dogs are a sub-species of wolf (Canis lupus familiaris) and as such, it is impossible to have a hybrid as they are two of the same species. Although technically incorrect, the term "hybrid" is the name which is predominantly used for these mixes and therefore it is the name we will also use when referring to them.

Designer Doggies• Aussiedoodle

Australian shepherd xPoodle

• CavapooCavalier King Charles xPoodle

• CheagleChihuahua xBeagle

• WEBSITE: http://www.dogbreedinfo.com/hybriddogs.htm

• List of Hybrid Dogs (Designer Dogs) (Boutique Dogs)

• The word ”hybrid,” when referring to genetics means, “the offspring of genetically dissimilar parents or stock, especially the offspring produced by breeding plants or animals of different varieties, species, or races.” In general, the word means, “something of mixed origin or composition.” Hybrid dogs, or designer dogs as some call them, are becoming quite popular. Below is a list of the most popular hybrid dogs. The best way to determine the traits of a mixed breed is to look up all breeds in the cross and know you can get any combination of any of the characteristics found in all breeds. The Dog Breed Info Center® does not attempt to interpret the temperaments of each individual hybrid mix because the differences in the dogs, even within the same litter, can vary greatly. If you do not feel the temperament of one of the purebreds in the mix is suited for your lifestyle, then that hybrid dog is not for you. Do not take a gamble that the puppy or dog will turn out like the other breed in the mix. Choosing a dog simply for its looks is a foolish way to choose a dog. Read the article on Designer Dogs for more info on these mixed breeds.

• Please Note: A hybrid dog is not a BREED; it is a hybrid, which means it is a mix of more than one purebred dog.

• Scientifically speaking, the term "hybrid” is incorrect as all dogs are a sub-species of wolf (Canis lupus familiaris) and as such, it is impossible to have a hybrid as they are two of the same species. Although technically incorrect, the term "hybrid" is the name which is predominantly used for these mixes and therefore it is the name we will also use when referring to them.

Inbreeding

• Inbreeding uses two genetically similar organisms, each being “the best of the best”

• Dog breeds are maintained by inbreeding• Characteristics that are unique to each breed are

preserved •Very prevalent in cattle farming – gives farmers the best possible livestock•Also can be very dangerous if two individuals have an underlying mutation

Biotechnology

• Biotechnology - when scientists purposely change the genetic makeup of an organism (Ex: introduce a mutation)

• Used in agriculture and medicine

• Bacterial mutations

A strain of bacteria has been developed that can digest oil to help clean oil spills

Scientists are trying to produce bacteria to clean up radioactive waste

Combining DNA Fragments

• Since DNA is a universal code, it can be combined from 2 or more sources

• Changes the genetic composition of the living organism

• This is called recombinant DNA• Can also be used to make proteins like human

insulin, hepatitis B vaccine, and a clotting factor for hemophilia patients

Transgenic Organisms• Scientists find specific genes and can add

them to any organism• Organisms with genes from other species are

called transgenic organisms• Ex: Red Fluorescent Protein (RFP) in cats• Cat with the GFP is red under UV light, while a

normal cat glows green• How did they do that…?

http://www.youtube.com/watch?v=YVdLJ78RBWk

Cloning

• A clone is a member of a population of genetically identical cells produced from a single cell

Genetic Modification

• If you’ve eaten corn, potatoes, or soy products this week, chances are you’ve eaten genetically modified (GM) food – it doesn’t have to be recorded on food labels!

• Many plants are genetically modified• Resistance to insects, herbicides (weed killer),

and viral infections• Resistance to rot or spoilage

Genetically Modified Animals

• 30% of milk in US comes from cows injected with hormones to increase milk production

• Pigs – produce more lean meat or high levels of healthy omega-3 acids

• Salmon – faster growth to produce more fish• Scientists in Canada combined spider genes

into lactating goats – produced silk along with their milk. Silk was extracted and used to make military uniforms, medical sutures, and tennis racket strings

Genetic Modification Good or Bad?

• Ideally, GM plants and animals could lead to better, less expensive, and more nutritious food as well as less-harmful manufacturing processes

• Farmers and ranchers hope cloning will allow them to duplicate prize animals, providing better quality and more food to a rising population

Recombinant DNA & Human Health

• Scientists can develop recombinant DNA to produce human antibodies to fight disease

• Can also make proteins engineered in transgenic sheep and pigs’ milk to be used in disease prevention

• Can treat diseases caused by protein deficiency

• Do you know of a disease/disorder caused by protein deficiency?

Gene Therapy

• Gene therapy – process of changing a gene to treat a medical disease/disorder

• Bad gene is replaced with a good gene• 1st – need a virus to transport the gene into the

organism• 2nd – patient’s cells are infected with the new

gene, hopefully correcting the defect• Challenging part – Will it last long term? Will

the virus DNA harm the patient?