epigenetics and human disease Flashcards
what did the dutch famine cohort study show?
exposure of embryo/fetus to famine
when there was famine in the first trimester there was higher risk of coronary heart disease
famine until second trimester = increased prevalence of obstructive airway disease
famine until third trimester = higher blood pressure at adulthood and mental diseases.
what is meant by epigenetic?
relating to or arising from non-genetic influences on gene expression
what was barkers early origins hypothesis?
intrauterine growth retardation, low birth weight and premature birth weight have a causal relationship to the origins of hypertensions, CHD, type 2 diabetes.
what is the thrust phenotype hypothesis?
low availability of nutrients during the prenatal stage followed by an improvement in nutritional availabilty of nutrients during the prenatal stage followed by and improvement in nutrition availability in early childhood causes and increase risk of metabolic disorder, including type 2 diabetes, as a result of permanent changes in the metabolic processing of glucose-insulin determined in utero.
what is the fatal origins hypothesis?
proposes that the period of gestation has significant impacts on the developmental health and wellbeing outcomes of an individual ranging from infancy to adulthood.
the effects if fatal origin are marked by three characteristics: latency, wherein effects may not be apparent until much later in life; persistency, whereby conditions resulting from fatal effect continue to exist for a given individual and genetic programming, which describes the switching on for a specific gene due to prenatal eviroments.
what does small and large body size of term babies have an increased risk for?
small –> adult CV disease, T2DM, osteoporosis, schizophrenia, depression
large –> cancer
what did a study she when mothers were fed a low protein diet for just 3 days from fertilisation to blastocyst stage?
causes offspring to exhibit CV disease:
- increased BP throughout adult life and at 15 and 21 weeks of age
- smaller heart mass in females
increase lung ACE activity (enzyme that increased blood vessel contraction
- reduced capacity to dilate arterial vessels
what the one gene one protein theory correct?
no, our genes are not set to produce the same gene, depends on environment - this is why cloned cat was not exact the same.
what is the epigenetic landscape? (waddington)
the epigenetic landscape is a visualisation of the interaction between genes and the environment by modelling the developmental pathways a cell cam take during differentiation.
“the process by which the genotype gives rise to the phenotype”
how can the same gene produce two different phenotypes?
hardware - genetics and DNA sequence (irreversible)
software - epigenetic - modifications on the DNA sequence - so some genes are expressed/not expressed = epigenetic of a person (epigenetic profile)
- -> histone acetylation
- ->histone methylation
- ->CpG DNA methylation
how stable is our epigenetic profile?
our lifestyle and disease can affect our epigenetic profile.
what is methylation?
DNA methylation is a process by which methyl groups are added to the DNA molecule. Methylation can change the activity of a DNA segment without changing the sequence. When located in a gene promoter, DNA methylation typically acts to repress gene transcription.
when is there high and low methylation?
high - in mature gametes, zygotes
low - fatal germ cells, embryo - blastocyst
the developing fetus had increasing methylation
is the conception environment important for health?
yes conception environment seems to be very important in defining health.
what does maternal embryonic communication regulate ?
features of blastocyst morphogenesis
coordination of implantation
maternal immuno-tolerance.
