Despite The Fact That Men Are Gradually Losing Their Y Chromosome, The Discovery Of A Novel Sex Gene In Spiny Rats Gives Humanity Hope

On the Y chromosome, there is a male-determining gene that determines the sex of newborn humans and other mammals. But unless we develop a new sex gene, the human Y chromosome will likely degenerate and disappear in a few million years, causing us to go extinct.
The good news is that two rodent species have previously lost their Y chromosome and survived.
A recent study published in Proceedings of the National Academy of Sciences demonstrates how the male-determinating gene of the spiny rat has developed.
How human sex is determined by the Y chromosome

Like other mammals, humans have two X chromosomes for females and one X and a little Y chromosome for males. The X stood for unknown, and the names have nothing to do with their shape.
About 900 genes in the X perform various tasks unrelated to sex. However, there are only about 55 genes in the Y, and most of the DNA is non-coding—simple repetitive DNA that doesn’t appear to do anything.
However, the Y chromosome is powerful because it has a crucial gene that initiates male development in the embryo. This master gene activates other genes that control the growth of the testis at around 12 weeks after conception. Male hormones (testosterone and its derivatives), which are produced by the embryonic testis, ensure that the baby develops into a boy.
SRY (sex region on the Y), the master sex gene, was discovered in 1990. It operates by initiating a genetic pathway that begins with the SOX9 gene, which, despite not being located on the sex chromosomes, is essential for the determination of the male gender in all vertebrates.
The vanishing Y
The majority of animals have X and Y chromosomes that are comparable to ours; the X has many genes, while the Y has SRY and a few additional genes. Due to the uneven dosage of X genes in males and females, this system has issues.
How did this peculiar arrangement come to be? The unexpected discovery is that Australia’s platypus has entirely distinct sex chromosomes that are more similar to those of birds.
The XY pair in platypus consists of two identical chromosomes, much like other chromosomes. This indicates that not so long ago, the animals X and Y were a typical pair of chromosomes.
This implies that over the 166 million years that humans and platypi have been developing independently, the Y chromosome has lost 900–55 active genes. A loss of five genes every million years is what that amounts to. In 11 million years, at this rate, the final 55 genes will be extinct.
There is controversy surrounding our claim that the human Y chromosome will soon disappear, and estimates of its predicted lifespan range from infinity to a few thousand years.
Species without the Y chromosome
We are aware of two mouse lineages that have already lost their Y chromosome yet are still surviving, which is fantastic news.
Both the Japanese spiny rats and the Eastern European mole voles exhibit species in which the Y chromosome and SRY have totally vanished. In either a single or double dose, the X chromosome is still present in both sexes.
A team led by Hokkaido University biologist Asato Kuroiwa has had more success studying the spiny rat, a group of three species found on various Japanese islands that are all endangered. It is still unclear how mole voles determine sex without the SRY gene.
The majority of the genes on the Y chromosome of spiny rats had been moved, according to Kuroiwa’s team. However, neither SRY nor the gene that acts as a stand-in was present.
Finally, a successful identification has been reported in PNAS. The researchers identified sequences in the genomes of male rats but not female rats. They then refined these sequences and tested each individual rat for the sequence.
What they found was a little variation close to the important sex gene SOX9 on chromosome 3 of the spiny rat. Only 17,000 base pairs out of more than 3 billion base pairs were duplicated, and it was found in all men but not in any females.
They assert that the switch that typically activates SOX9 in response to SRY is located inside this tiny fragment of duplicated DNA. They discovered that this duplication increases SOX9 activity in mice when they introduced it, suggesting that the modification might enable SOX9 to function without SRY.
What this implies for men’s future
Future scenarios have been discussed in light of the Y chromosome’s impending elimination, at least in evolutionary terms.
A process known as parthenogenesis allows some lizard and snake species, which are exclusively found in females, to create eggs from their own genes. However, neither humans nor other mammals can experience this because we have at least 30 essential genes that are imprinted and only function when passed on from the father through sperm.
Because men and sperm are required for reproduction, the loss of the Y chromosome may signal the end of the human race.
The latest discovery lends support to a different hypothesis, namely that a novel sex-specific gene may have evolved in humans. Phew!
However, there are dangers associated with the emergence of a new sex gene. What if different regions of the earth experience the emergence of multiple new systems?
The split of new species as a result of a battle of the sex genes has already occurred in mole voles and spiny rats.
As a result, if someone traveled to Earth in 11 million years, they might not find any people there or find a number of distinct human species, each with its own system for determining sex.

News Mania Desk