The Human Melting Pot

I came across this fascinating article on BBC with a title - Is Another Human Living Inside You? It's not a long article but it presents some startling ideas. Human genes are far more complicated than we thought.

It used to be thought that a baby had half of Mom's genes and half of Dad's genes - but that seems to be overly simplistic. Twins sometimes swap cells during their development in the womb. There are also individuals called Chimera who carry the genes of two individuals and a fully absorbed twin. This often happens during the earliest development of the fetus. What might start out as two fertilized eggs ends up merging into one individual. A study in Edmonton revealed that some women have male DNA in their brains - researchers speculate that it came from one of their male children during pregnancy. It seems to make them less susceptible to Alzheimers.

Fascinating! And raises all sorts of questions.

For example, could transgender people be carrying the genes of an absorbed twin of the opposite gender? That even though the body is male, there is a strong female presence.

The other idea presented was that we all carry microbes within our gut - often inherited from our parents. These microbes can produce  neurotransmitters that influence our behaviour - make us crave certain foods or behave in certain ways. The scary thing... meat from the grocery store can infect you with a nasty one...

An infection of a parasite called Toxoplasma gondii, meanwhile, might just lead you to your death. In nature, the microbe warps rats’ brains so that they are attracted to cats, which will then offer a cosy home for it to reproduce. But humans can be infected and subjected to the same kind of mind control too: the microbe seems to make someone risky, and increases the chance they will suffer from schizophrenia or suicidal depression. Currently, around a third of British meat carries this parasite, for instance – despite the fact an infection could contribute to these mental illnesses. “We should stop this,” says Kramer.

Can some mental health issues be attributed to what we eat? There is an old saying - "You are what you eat" - this takes it to a whole new level.

There is even some evidence that autism may be linked to gut bacteria.