Genetics Flashcards
What is genetics?
a branch of biology that studies inheritance
What are ways genetic improvement occurs?
selection, transgenic
What is Chester White?
a breed of swine that is the result of several years of genetic improvement through selection
How have genetic improvements occurred in dairy?
less cows are bred, but more milk is produced; cows were selected for more protein and fat in milk, and selected for health
What is feed efficiency?
6:1 down to 2.5:1 (feed intake : weight gain)
What are the benefits of feed efficiency?
save money and get to market faster
What is a genetic improvement in sheep?
wool production
How has genetic improvement affected chickens?
egg production; some Gallus domesticus strains can go up to 320 eggs per year
What are meat type chickens called? egg?
broilers; layers
How long are broilers kept? why?
6 weeks; after about 7 weeks they continuing growing until they plateau and develop leg problems
Why is AI used for domesticated turkeys?
sexual dimorphism, the males are too large
What is genetic improvement in beef cows?
less cows producing more meat
What is genetic improvement in horses?
There hasn’t been much change because selection is more for diseases and health than production; speed is almost maxed out in horses and there has to be a speed variant in order to breed it
What is linebreeding?
concentration of genes of a particular ancestor
How are genetic diseases inherited?
is a disease is a recessively inherited trait, have to be present in both parents in order for it to be shown; if dominant only shown in 1 parent
What is herritability?
degree of responsiveness, ratio of genetic variance to phenotypic variance; measures how much genetic variance is controlled by genes instead of environment
What is considered moderate to high herritability?
> 0.2
What is phenotype?
what you see
What is genotype?
genetic makeup
What is environment?
what is around (nutrition, housing, nourishment)
What is the equation for phenotype?
P=G+E
What is a gene?
basic unit of inheritance consisting of a DNA sequence at a specific location on a chromosome; a segment of DNA
What is DNA?
deoxyribonucleic acid
What is a chromosome?
one of a number of long strands of DNA and associated proteins present in the nucleus of every cell
Where are genes located?
on DNA
What are loci?
locations of chromosomes where genes are located (locus is looking at one location, loci is looking at many locations)
What are Mendel’s laws
Law of segregation, law of independent assortment
What is the law of segregation?
offspring receive one allele from each parent
What is the law of independent assortment?
alleles of the two (or more) different genes get sorted into gametes independently of one another (allele a gamete receives for one does not influence the allele received for another gene)
What is another name for phenotypes?
traits
What are simple mendelian genetics?
dominance, recessive, incomplete dominance
What is horned vs polled an example of?
dominant and recessive traits (if polled is dominant, when bred with a horned female the offspring is polled)
What is incomplete dominance?
see the expression of other alleles, majority of one and some of the other
In Mendel’s experiments, what was F1?
the first generation were all round, there were alleles for wrinkles but they were hidden
What is codominance?
2 alleles showing on phenotype at same degree (like a spotted dog)
What is TT?
homozygous
What is Tt?
heterozygous
What is qualitative?
controlled by 1 or few genes, divided into 2 discrete classes (is it present or not/ yes or no)
What is quantitative?
controlled by many genes, expression over a range (weight, height)
What type of trait is dystocia?
quantitative (despite being a yes or no)
Does the environment affect qualitative or quantitative traits?
quantitative
What does simply inherited mean?
few genes
What does polygenic mean?
many genes, polyfactorial (many factors)
What are the two types of genetic change?
natural selection and artificial selection
What does natural selection mean?
environmental influence
What does artificial selection mean?
human influence
Does natural selection still exist?
yes
What are the two types of breeding systems?
inbreeding and outbreeding
What is inbreeding?
mating individuals more related than the average of the population
What is outbreeding?
mating of individuals less related than the average of the population
Inbreeding is the _____ for all domestic animals?
basis
Does inbreeding cause mutations?
no, it doesn’t increase or cause mutations
What does inbreeding increase?
expression of genes and traits that are present, increases homozygosity
What are the types of inbreeding?
full seed, half seed, linebreeding (and mating of cousins)
What is full seed inbreeding?
same mother and father (or even breeding a parent and child)
What is half seed inbreeding?
only one parent in common
What are the two types of outbreeding?
crossbreeding, within breed/outcrossing
What are the genetic effects of inbreeding? phenotypic?
increase in homozygosity; inbreeding depression (reduced survival and fertility of offspring)
What are the genetic effects of outbreeding? phenotypic?
increase in heterozygosity; heterosis/hybrid vigor
What is crossbreeding?
breeding of animals of different breeds or species
What is outcrossing?
breeding within the breed
Can inbreeding happen in the wild?
yes, isolated animals will inbreed and can lead to extinction
What is heterosis?
hybrid vigor, an increase in the offspring performance over the purebreds parents
What is complementarity?
mating in individuals with different but complementary traits
What is crossbreeding used extensively in? What else?
meat producing animals (beef, swine, broilers, meat breeds of sheep); pets
What is crossbreeding rarely used in?
wool, horses, dairy, egg production
What environment do brangus do better in than angus?
dryer
Why isn’t crossbreeding used for dairy?
because they can’t be outperformed, production wouldn’t benefit but maybe fertility would
What is the genetic makeup of brangus?
5/8 angus x 3/8 brahman, the first generation has 50:50 so have to breed multiple times
What is genetic fitness?
ability to pass on genes and reproduce
What is nondisjunction?
failure of homologous chromosomes to separate, resulting in a daughter cell having both and then the other neither
Why can’t horses and donkeys produce fertile offspring?
horses have 64 chromosomes and donkeys have 62 chromosomes
What is a mule called?
a hybrid (he said chimera?)
How many chromosomes do cats have?
38 chromosomes
How many chromosomes do dogs have?
78 chromosomes
What are examples of undesirable crossbreeding effects?
mules and ligers
What is another name for embryo splitting?
low level cloning
What are the 4 types of genetic manipulation techniques?
natural mating, artificial insemination, embryo transfer, embryo splitting
What is embryo splitting?
after fertilization, as development begins, you can split the developing embryo into 2 or 3 during blastocyst stage, each split will grow into their own individual
Is a narrow genetic base good or bad?
bad, you want to increase the genetic base
You can trace every dairy cow back to ______.
35 males
Is artificial insemination used in chickens?
only some, usually fresh semen is used instead
Is artificial insemination used in beef cows?
a little, genetic improvement is not as great
For embryo transfer, what must be true for the donor and receiver?
have to be at the same reproductive state
How many embryos are inserted for embryo transfer?
multiple embryos because you don’t know if they all will develop; if more than 2 are inserted and they all develop they remove the extra
Do donor cows produce milk?
they are usually dry
Is embryo transfer cheap or expensive? why?
expensive because it is not guarenteed
How is embryo splitting done?
microdissection
What is selection?
determination of parents of the next generation
What is a triploidy?
have half complement of diploid chromosomes onto them, 1.5 the normal amount, have additional set of chromosomes (69)
How does a triploidy occur?
preventing the 2nd meiotic division results in the triploid
What are characteristics of a triploidy?
no genetic fitness, no reproduction, rapid/prolonged growth
Can triploidy happen naturally?
yes, but it is mostly induced by humans
What is cloning?
reproduction of a new animal from an existing animal
What kind of reproduction is cloning?
asexual
What is enucleation?
removing the nucleus
How does cloning occur generally?
put the nucleus of a cell from the animal you are trying to clone into the enucleated cell of another animal
Who was behind the research for Dolly the sheep?
Ian Wilmut
How was Dolly the sheep cloned?
the roslin method
What is the roslin method?
using electro cell manipulation (ECM); An egg cell that has had its nucleus removed is then placed in close proximity to a somatic cell and both cells are shocked with an electrical pulse. The cells fuse and the egg is allowed to develop into an embryo. The embryo is then implanted into a surrogate.
What do scientists want to clone and bring back from extinction?
the auroch
How would scientists clone the auroch?
by using the nucleus from Auroch remains and bovine/bison enucleated embryo
What is transgenic?
taking genes from one species and inserting into another species
What are examples of transgenic?
tobacco + luciferase gene, cats injected with jellyfish gene, animals inserted with antithrombin gene
Why were cats injected with jellyfish genes?
the macque gene is thought to protect against feline immunodeficiency virus (FIV) so it was inserted into cat embryo (caused the cats to have a fluorescent glow)
What is antithrombin?
a plasma protein with anticoagulant and anti-inflammatory properties
Why is antithrombin inserted into animals?
1 in 5,000 Americans are antithrombin deficient and have a high risk of clotting during surgery; genetically modified goats produce human antithrombin in their milk
What is propagate by natural breeding?
mating of animals by natural means (?)
What is rDNA?
r stands for recombinant; combining DNA for 2 or more organisms or species
What are traits of transgenic salmon?
grows faster but consumes less food; can reproduce (?)
What does CRISPR stand for?
Clustered Regularity Interspaces Short Palindromic Repeats
What is CRISPR successful in?
it is the most successful of all DNA editing technology
What does PRRS stand for?
Porcine Reproductive and Respiratory Syndrome
How many alleles can be identified that are different for each person?
13
How can DNA fingerprinting even be used?
everyone has a genetic footprint and unique DNA
What is DNA fingerprinting used for?
detecting whether an animal is a genetic carrier or not, identifying individuals, predict heterosis
How does DNA fingerprinting identifying individuals help?
theft recovery and pedigree verification
What is the purpose of detecting whether an animal is a genetic carrier?
so you can prevent an animal from mating, esp if autosomally passed down
What is the purpose of pedigree verification?
to tract ancestry and pedigree. check breed composition
What is the purpose of predicting heterosis?
less related individuals will express greater hybrid vigor in offspring
What is a histone?
protein that is wound around DNA
What is epigenetics?
genes can be turned on or off as a result of environmental effects
Does epigenetics affect the dominance of genes?
no
Are epigenetics permanent?
no, they are reversible and don’t change your DNA sequence but can change how a body reads a DNA sequence
What is DNA methylation?
the addition of a methyl group on the surface of DNA
What does DNA methylation and histone modification do?
alters DNA accessibility and chromatin structure. thereby regulating patterns of gene expression
What are benefits of genetic engineering?
food production and environment, medical issues
How does genetic engineering benefit food production and the environment?
- decreased pesticide/herbicide/fertilizers
- increased yields and productivity
- increased flavor and longevity
- increased nutrient content
What is an example of increased nutrient content?
rice fertilized with vitamin A
What are corn borer?
insects that attack corn
What is BT corn?
a genetically modified (GMO) corn that has genome from a bacteria infused into it and when insects feed on the corn they die
How does genetic engineering benefit medical issues?
- increased availability of drugs
- decreased cost of medical supplies
- decreased costs of hospitalizations
- custom transplant organs
- others not yet known
What is xenotransplantation?
organs from pigs transplanted into humans
What are risks and concerns of genetic engineering?
- genetically engineered organisms released into the general population
- long term effect on humans
- decrease in biodiversity (it narrows the genetic base)
- unethical/unlawful use of technology
