Genetics Flashcards
What is genetics?
The science of dealing with heredity and variation, seeking to discover laws governing similarities and differences in individuals related by decent
What are animal genetics?
study of the principles of inheritance in animals
What is animal breeding?
the application of the principles of animal genetics with the goal of improvement of animals
What is the purpose of animal breeding?
to improve genetically the economic efficiency of livestock production
What is the main tool in genetic improvement of economic merit?
selection
What is selection?
determination of the parents of the next generation
What are the two types of selection?
natural and artificial
Where does natural selection occur?
in nature
Where does artificial selection occur?
by humans
What is livestock improvement?
Change
What does selecting animals do (in terms of that graph)?
shift the mean
What is genetic fitness?
the capability of an organism to survive?
What are the characteristics of genetic fitness? (natural selection)
strength, size, intelligence, color, defense strategies, flexibility, longevity
Why is strength important?
animals must be able to survive to contribute to the next generation
Why is size important?
large animals are usually stronger and predators, smaller animals are able to hide and get away fast
Why is intelligence important?
If an animal is dumb, it won’t survive long
Why is color important?
camouflage, bright color warning of toxicity as seen in poison dart frogs
Why are defense strategies important?
can protect self, have fight or flight
Why is flexibility important?
flexible with nutrition allows animal to not rely on one single food source
Why is longevity important?
the longer they live, the more they can reproduce
What did domestication do for civilization?
it made it happen, shift away from hunters and gatherers
What are the three pathways of domestication?
commensal, prey, and directed
What animals followed the commensal pathway of domestication?
dogs and cats
What animals followed the prey pathway of domestication?
sheep, cattle, goat
What animals followed the directed pathway of domestication?
horses, donkeys, and camels or camelids
Who was Robert Bakewell?
father of animal breeding
What did Robert Bakewell invent?
purebred concept
What is purebred concept?
“in and in” mating system
What is a “in and in” mating system?
a kind of inbreeding
What was Robert Bakewell’s process?
set goals, developed early bull progeny test, developed record system
What is a bull progeny test?
testing offspring with a goal of evaluating bull parent
What does purebred concept result in?
as they mate you see a rise in uniformity and increase in homozygocity
What is a record system used for?
decisions are driven by records
What is the purpose of focusing on the male instead of the female (bull progeny test)?
it can change the population faster because the male can have more offspring
In terms of the bull progeny test for dairy cattle, what can you tell based on the daughters’ performance?
which bull is best for milk yield
What domestication process was used for commensal pathways?
self domestication/human intervention
What are the stages of self domestication/human intervention?
- selection for tameness
- strict captivity - limit breeding
- intentional breeding
- trait standardization
- eliminate wild species (genes)
What domestication process was used for prey and directed pathways?
human domestication/human intervention
What are the stages of human domestication/human intervention?
- control herd movement
- eliminate “problems”
- selection for tameness
- strict captivity - limit breeding
- intentional breeding
- trait standardization
- eliminate wild species (genes)
What major events in the 1800s led to development of modern genetics?
- Charles Darwin published The Origin of Species, describing theory of evolution by natural selection
- Gregor Mendel published Experiments in Plant Hybridization, which lays out the basic theory of genetics
- Friedrich Miescher isolated “nucleic acid” (DNA/RNA) from pus cells
What does Charles Darwin’s theory of evolution require to work?
heredity
How has milk production changed over the years? Why?
more production but less cows; we are genetically selecting animals to be more productive then they were
What does FE stand for?
Feed efficiency
How has swine production changed over time?
FE=6:1 down to 2.5:1 ; 6 pounds of feed for a pig to gain 1 pound of flesh is now down to 2.5 pounds of feed for 1 pound
How has wool production changed over time?
4x increase
How has egg production changed over time?
Jungle fowl produced 15 eggs a year and White Leghorn produces 300 eggs a year
How has broiler production changed over time?
12 weeks to 42 days (6 weeks) to reach size
How has turkey production changed over time?
AI is required due to selection for breast meat (the male is much larger than the female so it cannot breed on its own)
What do turkeys have as a result of selective breeding?
sexual size dimorphism
How has beef production changed over time?
little change in production
What is the only ruminant animal to have made a lot of progress in terms of production?
dairy
Why has there been little change in beef production?
the breed standards are constantly changing, one year a desirable bull could be large but another year it could be small
How has horse production changed over time?
little change, no change in speed index in 40 years
Why has there been little change in horse production?
It is hard to tell whether you are measuring genetic variance or variance of the traienr
How have dogs changed over time?
they are genetic wrecks
How have cats changed over time?
they are starting to become genetic wrecks
Why do dairy cattle have faster genetic/phenotypic change than beef? ????? need to listen to lecture
dairy cattle are bred commonly using AI, and AI isn’t used a lot in beef cattle
Why do sheep/goats have high genetic/phenotypic change?
gestation cycle is smaller (2 pregnancies in a year) and can have more offspring (twins)
What is estrus synchronization?
make all the animals go to heat at the same time
Why is having animals go into estrus synchronization good?
by having them go into heat at the same time, you get the best efficiency of AI and all animals go into birth at the same time
What animals is estrus synchronization used for?
dairy cattle and swine primarily
Who rediscovered Mendel’s work in 1900?
Robert Correns, Hugo de Vries, and Erich von Tschermak
Who was Archibald Garrod?
he discovered that alkaptonuria, a human disease, has a genetic basis
Who was Gregory Bateson?
discovered a linkage between genes and coins word “genetics”
What did Thomas Hunt Morgan do?
proves that genes are located on the chromosomes (using Drosphilia)
What did R. A. Fisher do?
studied quantitative genetics by partitioning phenotypic variance into a genetic and an environmental component (P=G+E)
What did Hermann J. Muller do?
showed that X rays can cause mutations
How do x rays cause mutations?
change in nucleotide base, changes type of protein made
What did Oswald Avery, Colin MacLeod, and Maclyn McCarty demonstrate?
DNA is the hereditary material (DNA is the transforming material, not proteins as previously thought)
Who showed that DNA can transform bacteria?
Oswald Avery, Colin MacLeod, and Maclyn McCarty
What did James Watson and Francis Crick do?
determined that the structure of the DNA molecule
What did Marshall Nirenberg do?
solve the genetic code, showing that 3 DNA bases code for 1 amino acid
What did Stanley Cohen and Herbert Boyer do?
combined DNA from two different species in vitro and transformed it into bacterial cells (DNA cloning)
What happened in 2001?
sequence of the entire human genome is announced
