Exam 1 Flashcards
Part of the chromosomes, that usually codifies a protein
Gene
Location on the chromosomes
Locus
Double helix made up of nucleotides
DNA
Specific form of the gene
Allele
What are the components for genes
Introns
Exons
regulatory areas
All of the DNA in chromosomes
Genomes
How many alleles does a individual have
2
What is homozygous
The 2 alleles are the same
What is heterozygous
The 2 alleles are different
Individual in the population have different sequences of nucleotides in their DNA
Polymorphism
Locations on the DNA where single nucleotides are different
Single Nucleotides Polymorphism (SNP_
Any part of the genome that affects traits of interest, Can be in coding or non coding regions
Quantitative trait loci (QTL)
What is the three Mendel’s Laws
Dominance and uniformity
Segregation
Independent assortment
What is dominance in Mendel First Law
Pure traits are crossed, only one form of trait appears in the next generation
What is Segregation in Mendel Laws
Mom and Dad two alleles
One of the allele from each is given to the offspring
What is Independent Assortment in Mendel’s Law
Alleles assort independently if possible
Do genes always assort independently?
NO because of linkage
loci located close together on a chromosomes
Linkage
The new combination of genes
Recombination
T or F More crossing over allow more genetic diversity
True
When do loci recombine, far apart or closely linked
far apart
The specific alleles the animal has at a locus
Genotype
the characteristic of the animal we are looking at
Trait
what we see when we look at an animal (measurement)
Phenotype
The black calf weight 85 lbs when it was born
trait: the color and the weight
Phenotype: the color black and 85 lbs
alleles interaction at two different location
Epistasis
What about endangered species or zoo animals?
Have small effective population size
4 Ways to change gene Frequencies in a population
Mutation
Migration
Selection
Random Drift
random change due to chance
Random drift
Why do We need to have a large population size
avoid the risk due to chance
a biochemical event causing a change in the DNA sequence
Mutation
Impact of mutation on animal improvement is very small or big
small
Gene editing Issues
- Regulations
- Do it before the animal is born
- Do it for a few animals
bring in alleles from outside the population - bring breeding animals into your herd
Migration
Why use migration (outside, native)
- Outside animals have higher frequency of desired alleles
- Native populations becoming too inbred and having problems
What is the most powerful gene frequency
Migration is the most powerful force for changing gene frequency.
choosing animals with high numbers of desired allele to be parents
Selection
what are the two types of selection
Natural Selection
Artificial Selection
animals which are unfit will die or fail to reproduce
Natural selection
selection imposed by human
artificial selection
The ability of animals of that genotype to reproduce
Fitness
If we are doing selection, we are changing what
frequency
Whenever q is large or small, you’ll see more changes in q
large
As s increase or decrease, change of q increase
increase
When we change gene frequency
We change the mean
Move the population in a desired direction
What animal breeders do?
Make decisions, select the parent of the next generation based on the traits of interest.
Do not need a numeric definition to accurately describe the trait
Qualitative traits
Traits are in a few phenotypic classes
Qualitative traits
Are categorical
Qualitative
Qualititave traits tend to
Be controlled by few or a lot of loci with large effects
Have little or a lot of effect of the environment
Be relatively easy or hard to manipulate through genetic management - relatively easy or hard to identify desired animals
Be controlled by FEW loci with large effects
Have LITTLE or NO effect of the environment
Be relatively EASY to manipulate through genetic management - relatively EASY to identify desired animals
What law does qualitative follow
Follow Mendels law
we know the genotype by looking at the phenotype
Single locus with co dominance, partial dominance, overdominance
the dominant allele completely masks the effect of the recessive allele. Heterozygous are the same as Homozygous dominant
Complete dominance
Why heterozygous animal sometimes bad
Heterozygous animal in a herd can be a carrier for a disease that is not desired
Why test males? Why not females?
Males usually produce more offspring
Importance/advantages of DNA testing
Heterozygous animal in a herd can be a carrier for a disease that is not desired, by sending sample and money you can find that out
Why do deleterious alleles tend to be recessive
Hiding in the heterozygous, not expressed when bred with a dominant allele
how to know if Is it Genetic or Environment
Prior knowledge about the defect
Look at housing and management groups
Look for family tendencies
What is already known, we may not know the mode of inheritance
Prior knowledge about the defect
Was there anything different in the way the animals were treated
Look at housing and management groups
Example of Look at housing and management groups
Issue with feed
Vaccination
Contamination
Check for carrier sire was in the past generation
Look for family tendencies
which one requires more work and which one is easier
environmental and genetics
environmental is easier
genetics requires more work
T or F Difference breed association have different policies
True
Offspring of carriers can’t be register until they are DNA tested
True
AI bulls must be tested for defects
True
AI sire needed to be tested free due to BLAD
holstein cattle
17% are carriers of hydrocephalus, cant get rid of this
Friesien horse
Does recessive always mean bad
no
Must be defined numerically to be accurately described
Quantitative traits