ANS 150 Exam 2 (Genetics)

Gene

Sequence of DNA that direct protein synthesis is very specific manner. These proteins in turn influence how traits are developed

mRNA

messenger RNA, template which directs assembly of amino acids into proteins

microRNA

RNA template that can block or disrupt protein production

genotype

the number and type of genes an animal possesses (genetic composition)

phenotype

the characteristics of an animals that can be seen or measured (outward appearance)

Genomics

--> genetic composition of animals
--> different genes

Epigenetics

--> heritable changes in gene expression that do not involve changes in DNA
--> same genes, different ones turned on/off

Proteonomics

--> proteins that are produced by a specific genome (or set of genes)
--> same genes, some ones turned on/off, proteins produced differently

Genotype + Environment = Phenotype

What is the equation for Phenotype?

Heritability

The proportion of variation or phenotypic differences among animals that is due to differences or variations in genotype.

eye color, coat color

What are examples of phenotypic traits that are 100% heritable?

Complete Dominance

--> one loci or gene, two forms of gene for alleles
--> B= black, b=red
--> will be black if homozygous dominant and heterozygous

Partial Dominance

--> example: Hyperkalemic periodic paralysis (HYPP) in horses
--> one loci, different forms of gene
--> HY = muscle spasms/tremors hy = normal physiology
--> phenotypical of heterozygote is similar to homozygous dominant but not as severe
--> HYHY= severe spams, HYhy= mild, hyhy =normal physiology

Overdominance

--> example: resistance to rat poison (Warfarin)
--> one loci, two different forms of gene
--> W=resistance, w=no resistance
--> phenotypic of heterozygote exceeds that of homozygous dominant
--> WW= resistant, but get a vitamin K deficiency when eat poison
--> Ww= resistant and healthy if they eat it
--> ww= die when eat poison

Epistasis

--> Interaction among genes at different loci
--> two loci (genes) each with two different forms of gene
--> ex: coat color in lab
--> B- first locus, black
--> E- second locus, extent of pigmentation genes
Black = B_E_
Yellow= _ _ ee
Chocolate= bb E _

Yes

Do the majority of traits involve both a genetic and environmental component?

Genetic Change

What does this describe: Selection Differential X Heritability

Selection Differential

superiority of selected animals compared to the average of a herd or group of animals (reach).

Bull weaning weight subtracted by Herd weaning weight

How to find selection differential

--> people who work in purebred industries
--> people that work with captive breeding of endangered species

Who is calculating inbreeding coefficients helpful for?

--> Adv: attempts to concentrate or increase the frequency of "advantageous traits"
--> Disadv: developmental and/or behavioral complications by increasing "undesirable traits"

Advantage and Disadvantage of Inbreeding Coefficients

Inbreeding Depression

What are the negative consequences referred to as?

--> Deleterious alleles become homozygous
(when close relatives mate)
-->Fewer, less viable offspring
--> Lower Survivorship
--> Increased chance of extinction

What are the consequences of Reduced Variation?

1. identify common ancestor(s)
2. check parents of common ancestor!
3. find generations to parents
4. add #3
5. Plug into Inbreeding Coefficient Formula
6. Change to %

Steps for Finding Inbreeding Coefficients

protein

everything that happens to the animal is based on...

Yes it is true, birth weight plays a huge role in animals like pigs, sheep, and goats. Birth weight, which is inheritable trait, determines how likely young neo-natal animals will survive.

Is it true that neonatal survival is not always based on the environment? Explain and provide examples.