Genetics Flashcards
what is the ultimate goal of the study of genetics?
genetic improvement
what is the effect of genetic manipulation on dairy cows?
35% more milk with 65% fewer cows
what is the effect of genetic manipulation on swine?
improved feed efficiency
what is the effect of genetic manipulation on sheep?
4x more wool production
what is the effect of genetic manipulation on egg production?
from 15 eggs/yr with jungle fowl to 250 eggs/yr with white leghorns
what is the effect of genetic manipulation on broilers?
went from 12 wks to 56 days to mature
what is the effect of genetic manipulation on turkey?
AI is now required for reproduction due to selection for breast meat (white v. dark)
what is the effect of genetic manipulation on beef cows?
little change in production overall
what is the effect of genetic manipulation on horses?
no change in speed index in last 40 yrs, but through selection, genetic diseases are more prevalent
what is the effect of genetic manipulation on dogs and cats?
genetically tortured, very specific selection = lots of disorders and physiological problems
what is the equation for genetic phenotype?
P = G + E, phenotype = geneotype + environment
what three things control genotype?
genes, DNA, chromosomes
define gene
a DNA sequence on the chromosome that codes for a biologically important molecule
what does DNA stand for?
deoxyribose nucleic acid
define chromosome
one of a number of long stands of DNA and associated proteins present in the nucleus of every cell
how is gene expression determined in animals?
Mendelian genetics; dominant and recessive genes
AA equals?
A
Aa equals?
A
aa equals?
a
what is incomplete dominance? give an example
a mix of both dominant and recessive genes; shorthorn cattle roan coat color
what is the importance and heterozygous and homozygous?
both genes have a 50/50 shot of being passed on
what are the types of traits?
qualitative, simply inherited, and quantitative, polygenic
define qualitative traits
discrete classes, yes/no, black/red
define simply inherited traits, give an example
few genes control trait color
define quaNtitative traits, give examples
expression over a range, numbers; weight, height
define polygenic traits, give examples
many genes control trait; weight speed
which traits are easier to modify? give examples
qualitative/simply inherited; eye color, hair/coat color
which traits are more economically important? give examples
quantitative/polygenic; speed, weight, height, wool production, litter size, muscle, milk production, fertility, disease
what are the exceptions to the trait classifications?
pregnancy and dystocia, it’s a yes/no question that is determined by many factors
what are the two selection types for genetic change?
natural selection and artificial selection
define natural selection
environmental influence
describe artificial selection
human influence
does natural selection still exist?
yes, but it’s limited
what type of selection do mating systems fall under, and how many are there?
2, artificial selection
what are the two mating systems?
inbreeding and outbreeding
what is inbreeding?
mating individuals within a breed who are more related than average of population
what is linebreeding?
a type of inbreeding that involves concentrating the genes of a particular ancestor
what is outbreeding?
mating individuals within a breed who are less related than average population
what are some other names/types of outbreeding?
outcrossing, cross breeding
what is the basis for all breeds of domestic animals?
inbreeding
does inbreeding increase or cause genetic mutations?
no, it just increases expression of recessive genes and traits that are present, increases homozygosity
how did we get domestic animals from wild animals?
inbreeding
what two common domesticated animal groups often use outbreeding?
pets and livestock
what is heterosis?
offspring perform better than the average of the parents, and increase in performance over the purebred parents
what is complimentarity?
improvement in the performance of the crossbred offspring resulting from mating individuals with different but complimentary traits
where are heterosis and complimentarity used extensively?
meat producing animals, like beef, swine, meat sheep/goats
why is heterosis and complimentarity used extensively in meat producing animals?
enhances production and favorable (or not detrimental) influence on other traits
where is heterosis and complimentarity (outbreeding) also used and why?
pets, like dogs and cats; it’s often not economically beneficial, doesn’t enhance reproduction, and often has less desirable influences on other traits but MAN are they cute
what do you get when you cross a Hereford (Bos taurus) and an Angus (Bos taurus)?
a Black Baldy, with heterosis of increasedp reproduction, weaning weight, and survivability, but no complimentarity because they are too closely related
what do you get when you cross an Angus (Bos taurus) and a Brahman (Bos indicus)?
a Brahman, with heterosis of increased reproduction, weaning weight , and survivability, and complimentarity of heat tolerance and parasite resistance
what do you get when you cross a horse and a donkey?
a mule, which is a chimera with no genetic fitness, so it’s unable to reproduce
what is genetic fitness?
ability to pass on genes and reproduce
what do you get when you cross a bison and cattle?
Beefalo! which must be 3/8 or less Bison to reproduce
what do you get when you cross a lion and a tiger?
a Liger, which can’t reproduce
what do you get when you cross a tiger and a lion?
a Tigon, which can’t reproduce
what is simple genetic manipulation
selection, or determining the parents of the next generation
what are the four genetic selection techniques?
natural mating, artificial insemination, embryo transfer, and embryo splitting
what is the potential and rate of genetic change for natural mating?
slow and slow
what is the potential and rate of genetic change for artificial insemination?
potential: moderate
rate: fast
what is the potential and rate of genetic change for embryo transfer?
potential: high
rate: slow
what is the potential and rate of genetic change for embryo splitting?
potential: high
rate: slow
in what animals is artificial insemination used a lot?
turkeys, dairy cows, and swine
in what animals is artificial insemination used less?
chickens, horses, beef cows, sheep, goats
how does the success rate of embryo transfer compare to that of artificial insemination?
it has a lower success rate
in what animals is embryo transfer used?
dairy cows, beef cows, horses
how do you collect embryos for transfer?
give drugs to two cows to synchronize their cycles, super ovulate the donor by giving her FSH, give an epidural, fertilize the eggs, and pump in solution to flush eggs out
how do you transplant embryos?
just like AI, but you have to pay attention to which side the recipient last ovulated on for her corpus luteum, then deposit the embryos 2/3 up the uterine horns on the side with the CL
what does embryo splitting do?
creates twins
can you split an embryo an unlimited number of times?
no, the embryo’s genetic info is limited
how do you make a triploidy?
prevent the 2nd mitotic division in the ovum, and then fertilize with normal sperm
what is the equation for triploidy?
1n + 2n = 3n
can triploidy reproduce?
no, they have no genetic fitness
what is the advantage of triploidy?
rapid/prolonged/continued growth
what is cloning?
the reproduction of a new animal from an existing animal
what was the first animal to be cloned?
frogs
what was the second animal to be cloned, what was her name, and how many tries did it take?
sheep, Dolly, 277
what company clones your pet?
ViaGen, for 50K
what is the modern day Jurassic Park scenario?
scientist trying to resurrect or breed back to aurochs
what is transgenic?
taking genes from one species and inserting them into another species
give an example of transgenic research in plants?
inserting the Luciferase gene from fireflies into tobacco plants to make them glow
what is an example of transgenic research with cats and monkeys?
inserting the macaque gene from monkeys, which is thought to protect against FIV, into a cat embryo, along with a bioluminescent jellyfish gene as an observable phenotype to gauge success
what is an example of transgenic research with goats?
removal of the human antithrombin (anticoagulant and anti-inflammatory) gene from humans, putting it into goat embryos, creating clones with the gene, letting them multiply by natural breeding, and then collecting the milk they produce (which carries the antithrombin gene) and making it into a pill for deficient humans to take
give an example of transgenic research that may hit the food market soon?
triploidy transgenic salmon; Atlantic Salmon with genes from Chinook Salmon and Ocean Pout that grow really big really fast
what is CRISPR and give an example of an animal made through this process?
precise genome editing, PRRS resistant pigs
what does DNA fingerprinting determine?
- genetic carriers (or not) of diseases
- identify individuals: pedigree verification, theft recovery
- predict heterosis: less related individuals will express greater hybrid vigor in offpring
what is epigenetics?
genes turned on or off as a result of environment effects
give an example of epigenetics in animals?
bees are genetic clones of the queen, but the environmental factor of eating royal jelly or worker jelly determines if they’ll be a worker bee or a queen bee
give a example of epigenetics in humans?
air pollution turns on asthma gene
what are the benefits of genetic engineering in food production and the environment?
- decreased pesticide/herbicide/fertilizer usage
- increased yields and productivity
- increased flavor and longevity
- increased nutrient content
what are the benefits of genetic engineering in the medical field?
- increased availability of drugs
- decreased cost of medical supplies and hospital visits
- custom transplant organs
- other benefits not yet know, being explored
what are the risks and concerns of genetic engineering?
- genetically engineered organisms being released into general population
- long term effect on humans
- decrease in biodiversity
- unethical/unlawful use of technology
