Epigenetics Telegony and Fatherhood

A statement about telegony. Has a new mode of inheritance been uncovered?

This article is going to discuss inheritance and genetics and a new finding that may affect how we view inheritance. We are all very familiar with genetic inheritance, that is that each one of us has inherited our father’s and our mother’s DNA material. The combination of their DNA material is expressed in proteins and different types of cellular types that eventually have formed us. In fact, our current level of understanding only contains genetic inheritance which may be affected by epigenetic influences to your environment. Therefore, I want to discuss with you a different mode of inheritance, called telegony and the paper is cited below (1).

For those that are lazy and do not want to read the paper I will quickly summarise it here. This paper included an experiment (1) with, initially, virgin flies. From these flies, they mated the females with first sterilised male flies which still produced semen and following two weeks they mated those female flies again with non-sterilised male flies. The experiment results showed that the resulting offspring closer resembled to the phenotype of the sterile flies, while the PCR analysis showed that the resulting offspring were the direct genetic descendants of the non-sterilised flies. The results were shocking, which lead to a page and half of discussion.

And this is where things get interesting. The most important question to ask following this is… is the experiment relevant? Yes it is as it questions our current level of understanding and brings forward many worthwhile questions. Are the results statistically significant? Well apparently so. Are the methods they used appropriate? Yes. Therefore, the next and most important question is. What affects DNA expression in these animals if there is no DNA transfer? Well the answer to that is that, we simply do not know. The authors have termed this phenomenon telegony.

However, something must be affecting the DNA expression, as for the phenotype to change proteins from the DNA need to be expressed. There must be an epigenetic effect acting on the DNA. And if there is no male DNA there, then the epigenetic effect must be acting on the female DNA, the female eggs that are sitting there. How that happens? Well I personally have no idea, and no-one really has any idea at present. But let’s present the case for humans. Is such an effect possible for humans? If you consider that the majority of earlier experiments regarding DNA have occurred on fruit flies. The results become a lot more relevant.

Now anatomically speaking I don’t see this as not possible. The woman’s reproductive organs allow for the sperm and semen transfer from vagina, to uterus, up the Fallopian tubes and then they escape  into the abdominal cavity, where they are broken down and cleaved away by white cells. But if you pay attention very closely to the diagram below, the ovary is based very close to the Fimbriae which is the opening of the Fallopian tube. Therefore we have the potential that some of the semen and sperm will wash over that area.

Theoretically speaking, if this effect is real in mammals, this can mean that the potential implications are, that semen alone, containing within an epigenetic profile modifier, may affect the DNA expression of the eggs inside the ovary. You see females are born with all the eggs they will ever have. Therefore, all those eggs sitting there could be getting modified epigenetically by each one of the sexual partners of a female.

I know that this sounds almost ludicrous but the evidence is there. However, there is a greater problem with all of this. If the effect is noticeable in flies, which of course is a much smaller animal than ourselves, this effect could be noticeable in humans in epigenetic terms. I will discuss more about epigenetics later. But let’s assume that a gene or a strand of DNA will be expressed differently if there is a different epigenetic modifier acting upon it. Therefore if this effect is real it has many potential implications on the resulting phenotype. That is the proteins that cells may express in all the organs of the human body.

This brings us to an even more interesting part to newer and more notable research involving humans and monkeys. The impression so far has been that our immune system will attack and destroy foreign cells. This is to say, any cells that belong to someone else will be cleared off by our immune system as they possess foreign DNA, and express different identifying proteins that our immune system recognises and produces antibodies against.

Recently, microchimerism has been discovered in the brains of females. That means that Y chromosomes have been identified in the brains of deceased females. (2) This is something that should not be happening but evidence all around us tells us that it is happening. The results are replicated in rhesus monkeys (3) and additionally scientists suspect that those Y chromosomes are not just sitting there but they also have a function (4).

This article will not discuss the function of the Y chromosome in the female brain. However, the implications that the mere presence of the Y chromosome may have when we are discussing telegony are vast. This means that male cells can potentially survive inside the female body. Theoretically those Y chromosomes do not simply exist on their own, but they exist inside their own cells. These cells are presumed to have come from the fetus that the woman kept inside of her for 9 months. However, some of the females with Y chromosomes in them, never gave birth. However, they could have been pregnant and lost the baby. But where those cells come from is not really the subject of the discussion, because that Y chromosome is identical to the Y chromosome of the father and hence the partner.

While antigens from another human being are usually recognised by the immune system as foreign and are thus attacked. These Y chromosomes contained within cells are allowed to exist within the female for many years. That is they are never attacked by the immune system. The brain, gametes and eyes are parts of the human body whereby the immune response is usually highly modified and reduced (5). These areas form privileged areas of the immune system. As such they are areas where such a foreign body, such as a cell is more likely to exist without much interference from our immune system.

By considering these studies (2) (3) (4) (5), is it really that unlikely that the ovaries containing the eggs from birth can be epigenetically

modified by the presence of semen inside a woman? With the increase in the amount of sexual partners, your child might be your child, but epigenetically whose child is it really? I know this sounds like a strange question but consider the action of epigenetics for a moment. 

First let’s consider an epigenetics definition.  The DNA is wrapped around nucleosomes, and further compacted such as in the picture above to form chromosomes. The epigenetic proteins are used to uncoil the DNA and allow each cell to express specific genes. In actual fact this is how phenotype is made. The effects of the DNA expression are largely affected by what way the DNA is folded and what part of is accessible to be transcribed. Small changes in the environment awaken different genes and although, how this occurs is largely a mystery, many epigenetic mechanisms have been  identified. Therefore, epigenetic changes occurring at the level of the egg or somewhere else that we have yet to identify, can play a huge role in the latter on expression of genes, the overall phenotype of that organism,  and potentially affect the predisposition of that organism to genetically linked diseases.

This article is largely speculation. But the evidence is there for the speculation to occur. There is also a hangout whereby I discussed with Dark Knight (6) about the potential implications of the Telegony study (1). However, knowing what we know now, the floodgates are open for further research to occur and for the truth to be uncovered.

 

References:

Revisiting telegony: offspring inherit an acquired characteristic of their mother’s previous mate. http://onlinelibrary.wiley.com/doi/10.1111/ele.12373/abstract

Chan WFN, Gurnot C, Montine TJ, Sonnen JA, Guthrie KA, et al. (2012) Male Microchimerism in the Human Female Brain. PLoS ONE 7(9): e45592.doi:10.1371/journal.pone.0045592

Bakkour S, Barker RCA, Tarantal AF, Wen L, Busch MP et al. Analysis of maternal microchimerism in rhesus monkeys (Macaca mulatta) using real-time quantitative PCR amplification of MHC polymorphisms. Chimerism 5:1, 6–15; January/February/March 2014

Kopsida et al. The Role of the Y Chromosome in Brain Function; Open Neuroendocrinol J. 2009 ; 2: 20–30.

Perez VL, Saeed AM, Tan Y, Urbieta M, Cruz-Guilloty F. The eye: A window to the soul of the immune system.

Dark Knight, Niko Choski. Conversation with Dark Knight: Are we all fathers? https://www.youtube.com/watch?v=iaOpch-9Y4E

Edit:  On top of Nikos excellent article I wish to provide more resources starting first with the definition of telegony:

Telegony is a theory in heredity, holding that offspring can inherit the characteristics of a previous mate of the female parent; thus the child of a widowed or remarried woman might partake of traits of a previous husband. Experiments on several species failed to provide any evidence that offspring would inherit any character from their mother’s previous mates.[1][medical citation needed] A similar phenomenon, whereby environmental (non-genetic) traits were passed, was later discovered in a species of fly.

This is not to be confused with the greek poets work the telegony or The Death of Odysseus in the Odyssey and the Telegony, although the word likely has its etymological origin it.

A short counter opinion expressed in qoura about telegony in humans titled is telegony real for humans states the following:

The short answer is “no”.

The slightly longer answer is that despite a recent study in fruit flies, (a) human beings are too distant from fruit flies to extrapolate meaningfully, and (b) it only shows up in fruit flies because we can control their genetics and environment to an excruciating degree. There are thousands of environmental, nutritional, and hormonal factors that go into the womb environment. Any equivalent effect in human beings, if there is one at all, would be massively swamped by other factors.

So it’s deeply misleading to name it after a bit of folk wisdom. It goes back to Aristotle, and as usual, every word out of the man’s mouth on scientific matters was wrong. The folk understanding of it is completely at odds even with the phenomenon discovered in fruit flies, and reviving the name confuses more than it clarifies.

To me it sounds as if this guy simply does not want telegony to be real, he sites no genetic studies to support his claim.  but i figure i’d at least post it.