The process we know about is quite simple: Egg meets the sperm, fertilization occurs and babies are formed. But in reality, it’s not that simple. Get introduced to the feminine receptivity or the freedom of choice for women. It’s actually the female eggs that choose.
Scott Gilbert, a developmental biologist at Swarthmore College believes that the egg engages in a “dialogue” with the sperm, rather than lock it down. The fertilization is more of a fair race than a conquest.
It has also been proven that eggs attract a particular kind of sperm if given the change, and we are thrilled to have come across the research that proves that eggs can be choosy and have their own pick.
The popular notion is that of the race of the sperm
Almost everyone believes that the sperm races toward the egg. The race begins when the sperm is ready, and the egg is at its healthiest. Millions of sperm head towards the egg cell, and when an X meets a Y, it’s a boy, or when an X meets an X, it’s a girl.
Now, let’s begin the process of unlearning.
The female egg refuses to be submissive, and instead, they choose their own sperm.
It’s not an actual race, since the winner has already been decided. The egg has chosen the type of sperm that it will allow entering, because the eggs are a key player in the process of reproduction. Dr Joseph H. Nadeau explains that against the popular notion, it’s actually the other way around.
The egg favours or discards the sperm, making the sexual selection at the cellular level more complex. It’s amazing how such an obvious process has been evaluated wrongly all this time.
How was Mendel’s law defied?
According to the Mendel’s Law, each parent carries 2 copies of each gene. Next, the random fertilization takes place, and the genes are randomly divided into gametes that carry only one copy.
However, recent studies discarded this law by conducting 2 separate experiments that hinted towards a different theory.
Dr Nadeau couldn’t produce specific predictable ratios of gene combinations in offspring, based on Mendel’s laws.
He gave female mice one normal and one mutant gene that increased the chance of getting cancer, and male mice had all normal genes, as part of his experiment. The result came in accordance with Mendel’s law.
In the second experiment, Dr Nadeau reversed the breeding. The mutant cancerous gene was given to the male mice, and the female mice had normal genes. And that was the moment that defied the Mendel’s Law. Only 27% of the mice received the mutant version, while the doctors were expecting it to be 75%.
What was proven with this experiment is that the fertilization is not random, and that there is an existence of a mechanism that allows the egg to choose the sperm with the normal instead of the mutated gene. It’s called ‘genetically biased fertilization’ in scientific terms.
What does that mean?
Was the case always like this, and it managed to skip the eye of the scientists?
Dr Nadeau believes there are two possibilities for this.
1. The attraction between the sperm and the egg involves the molecule of folic acid largely, meaning that the changes the metabolism of B vitamin or folic acid in the egg and the sperm may be the deciding factor for their attraction.
2. Sperm is already present in the female reproductive tract when they are headed towards the egg, so the egg may not be fully developed during this time. The egg may be influencing the cell-division, and the genes can be well-suited to the sperm.
We think that this information should be shared further, and we hope that it makes the picture a little more clear.