Wk12 in utero factors affecting postnatal health

Question 1

Epigenetics definition

Answer 1

• Non-coding changes to the genome which alter the expression of genes
  2 types of epigenetics: DNA and histone methylation and non-coding RNA’s

Question 2

What is the barker hypothesis on DOHad

Answer 2

Concept that offspring adult health can be determined by exposures either in utero or to parents (F0 - first generation) prior to conception (maternal/paternal effects)
- Foetal development influenced by what the parents do/act
By altering pre-conception and gestational environments, we can impact long term offspring health and productivity

Question 3

Epigenetic molecule mechanisms: histone and DNA methylations

Answer 3

• Histone and DNA methylations = switching genes on/off by controlling access to DNA
  
  • Changes the physical state of the DNA and how likely it is to be expressed
    Cytosine methylation (C gene) and DNA binding protein methylation

Question 4

Epigenetic molecule mechanisms: non-coding RNAs

Answer 4

• Non-coding RNAS = altering methylation or RNA translation
  
  • Micro-RNAs and degradation of mRNA
  • Altering methylation
    Ends up turning off gene expression for particular genes. One non-coding mRNA can turn of 100s of genes

Question 5

What effects the epigenome / impact offspring development?

Answer 5

• Many factors, including diet, stress, disease, toxins, parental age, physical activity etc.

Question 6

Epigenetic inheritance: what effects this - 2 facets:

Answer 6

• Can be limited to direct exposure = (intergenerational)
• Or continue without direct exposure = (transgenerational)

Potential to take advantage of this for beneficial production

Question 7

Which of the following is NOT an epigenetic molecular mechanism?
- Protein phosphorylation
- DNA binding protein methylation
- Cytosine methylation
Micro RNA

Answer 7

• Protein phosphorylation

The other 3 are examples of histone and DNA methylations, and non-coding RNAs

Question 8

How could we potentially use maternal and paternal effects to our benefit?
What are some potential limitations?

Answer 8

• We can use genetics to our advantage for breeding purposes
  
  • We can control/improve productivity in our offspring*
  • We can change genetics to improve welfare of offspring
  • We can change animal management for beneficial epigenetic effects
• Limitations:
  
  • Lack of knowledge
  • Parental welfare
    Are the genes heritable?

Question 9

DOHaD gestation effects (developmental origins of health and disease):

Answer 9

• Things that have occurred to the mother during gestation period
  • i.e. Mother getting mastitis can lead to significant decrease of survival and production.
    Diet of the mother - concentrate in mare have higher chance of getting disrupted bone development compared to mares eating forage during gestation

Question 10

DOHaD - parental effects

Answer 10

• Each parent on the phenotype of the offspring via mechanisms other than allele inheritance
  Diet of the father of offspring can effect offspring health