epigenetics

Darwin first conceived the theory of evolution by natural selection, and that adaptive heritable characteristics were passed on from parent to offspring. This led to the publication of “origin of the species”

show the chance of a dominate and recessive gene, specifically an allele being passed from parent to offspring

Out of the 23 pairs of chromosomes we have in ur DNA, 1-22 are called autosomes, and the 23rd is the sex chromosome (XX for females, as here, or XY for males). We inherit one chromosome from each of our parents

Alleles are alternate forms of a gene inherited one from the father and one from the mother (and so found on corresponding sites on homologous chromosomes). There can be dominant and recessive versions of the gene. In any combination with the dominant version, it is the one that is expressed. The recessive only expresses in the absence of the dominant.

Genes are responsible for the type of the body they express (e.g., the eye colour). Alleles dictate what the characteristic of that body part is expressed (e.g., blue, brown, green, grey, etc)

for example Huntingdon’s. means it is always carried on the dominant gene. Therefore, when one parent has it, it expresses 50% of the time. If both parents have it, there is a 75% chance of the child inheriting.

schizphrenia We can look at concordance for a variety of phenomena by exploring the degree to which individuals are biological related and/or have shared environments. Individuals who do not have a shared environment BUT have a biological parent who has schizophrenia have a 9x higher chance of developing schizophrenia than is observed in the general population.

schizophrenia The concordance rate, the probability that a second twin will develop a disorder if the proband (first examined) twin has the disorder, is commonly used. The concordance rates of schizophrenia for monozygotic twins have been found to be about 40 to 50%, and heritability estimates are around 80%.

Turkenheimer (2000), Chabris et al., (2015) • All human behavioural trait are heritable • The effect of the genes is larger than the effect of the shared environment • A lot of variance is not attributable to either genes or shared environment . Most complex traits are shaped by many genes of small effect

Chromosomes are a packaging system for DNA, and form the essential unit in cell division. It is wound around spool-like histone proteins such that the total of about 2 metres of DNA in our cells can be packing into about 0.1 mm of chromatin (Adenine-Thymine and Guanine-Cytosine)

To replicate, the strands unwind; each nucleotide attracts its complementary base (floating about in the cell nucleus), making two DNA molecules identical to the original Replication errors affecting particular genes are called mutations

just having a gene doesn’t do a whole lot. It’s only when the gene expresses itself (by triggering protein synthesis) that it has an effect. Gene expression depends heavily on the organisms internal and external environment

involvement of multiple genes in 1 trait e.g. ADHD – 33 genes

involvement of one gene in multiple traits e.g. phenylketonuria

RNA methylation DNA methylation Histone acetylation

• Parents create environment to suit their genetic predispositions • This can enhance children’s inherited characteristics

• People have inherited tendencies to evoke certain responses • These evoked responses reinforce inherited characteristics

• People select/create environments compatible with their inherited characteristics • The resulting experiences enhance the effects of inheritance

long term effects on dutch population starvation had long lasting effects on the body, even after food was normal Barker proposed that a situation where there is an adverse fetal environment (e.g, shortage of food), followed by a plentiful food environment may be a recipe for adult chronic disease.

revealed that the children of women who had starved during the Hunger Winter had health problems: including higher rates of diabetes, obesity, and cardiovascular disease.

• Glucose intolerance - Glucose intolerance is an umbrella term for metabolic conditions which result in higher than normal blood glucose levels - hyperglycemia. Associated with T2 diabetes

• Glucose intolerance • Microalbuminuria - Microalbuminuria means that there’s more of a protein called albumin leaking from your kidneys into your urine than normal. Associated with high blood pressure and diabetes • Obstructive airway disease

• Glucose intolerance • Hyperlipidaemia – hyperlipidaemia means your blood has too many lipids (or fats), such as cholesterol and triglycerides. One type of hyperlipidaemia , hypercholesterolemia, means there’s too much LDL (bad) cholesterol in your blood.

Intrauterine exposures that have long-lasting consequences for adult health do not necessarily result in altered birth weight. Women exposed to the famine during mid- to late gestation had babies with significantly reduced birth weights. Babies whose mothers were exposed only during early gestation had normal birth weights; however, they grew up to have higher rates of obesity than those born before and after the war and higher rates than those exposed during mid- to late gestation