The Future of Mankind

Why is there always something to worry about? Or is it just me that regularly seems to bite into the only unpitted olive in the container? The only person who finds the camouflaged husk in the just-microwaved bowl of frozen corn? All is not as it appears to be, and as a participating member of a species atavistically wedded to pattern recognition, I don’t think this is healthy.

Of course, there is always the argument that many of those things that point in my direction are statistically anomalous, but I find that to be of little comfort, let alone reassuring. That I have more chance of dying in an automobile accident than being awarded a Giller Prize for my writing may be seen as obvious to some, but it leaves a lot of scope for improvement.

Lately, however, I find that my concerns are shifting; I am learning to deal with them constructively. Although I still am cautious each time I boil rice, I no longer scan the grains for little legs -okay, I’m tempted… but I find that cooking it a few extra minutes grants me the peace of mind I thought possible only after a glass of wine. Maybe it’s just my memory, but some things seem to be becoming more easily manageable -well, ignorable, at any rate.

On the other hand, I’m probably only skimming the surface now, blissfully unaware of the shoals that are certain to appear at the next low tide. But, on reflection, I have come to wonder whether it is nobler in the mind to suffer the slings and arrows of outrageous fortune, or to take arms against a sea of troubles, and by opposing, end them. Sorry, that just popped into my head for a moment.

Anyway, do you see my point? Sometimes it is important to know what’s going on just out of sight. Closing one’s mind, like closing one’s eyes, does not really make anything disappear -except maybe little legs and stuff. Sometimes you just have to man up… although, it seems as if that, too, may soon be just another anachronism stored on a back shelf somewhere.

Anyway, I wish I weren’t so curious: apparently the Y chromosome is now in trouble. In an article in The Conversation, Darren Griffin, professor of Genetics at the University of Kent, and Peter Ellis, a lecturer in molecular biology and reproduction at the same university discuss the ramifications for the poor Y – Yes! The Y chromosome! The bastion of masculinity, the sine qua non is shrivelling away like a candle that has burned too long. And I doubt if it is amenable to my usual solution of simply boiling it longer.

I hate to say I told you so, but even in medical school I wondered why it was so small. The X chromosome is a giant compared to the gentle Y. It’s no wonder women won’t have anything to do with it -I mean, if you don’t need one, why keep it in your purse?

And, apart from carrying the SRY gene ‘that determines whether an embryo will develop as a male (XY) or female (XX) it contains very few other genes and is the only chromosome not necessary for life.’ Great! We’re just an extra, hired for a special job -like drone bees, to fertilize the queen- but otherwise essentially redundant. Replaceable…

‘What’s more, the Y chromosome has degenerated rapidly, leaving females with two perfectly normal X chromosomes, but males with an X and a shrivelled Y. If the same rate of degeneration continues, the Y chromosome has just 4.6 million years left before it disappears completely.’ Some things are just not fair. I’m surprised we got the vote first…

But, ‘The Y chromosome hasn’t always been like this. If we rewind the clock to 166m years ago, to the very first mammals, the story was completely different. The early “proto-Y” chromosome was originally the same size as the X chromosome and contained all the same genes. However, Y chromosomes have a fundamental flaw. Unlike all other chromosomes, which we have two copies of in each of our cells, Y chromosomes are only ever present as a single copy, passed from fathers to their sons.

‘This means that genes on the Y chromosome cannot undergo genetic recombination, the “shuffling” of genes that occurs in each generation which helps to eliminate damaging gene mutations. Deprived of the benefits of recombination, Y chromosomal genes degenerate over time and are eventually lost from the genome.’

It’s not sounding very good, guys! We’re carrying around what amounts to memories, not machinery. We are clinging to the Y like a desperate child to his mother’s skirt. Of course there have been a few feeble attempts to hold on more tightly, but maybe too little, too late. ‘For example, a recent Danish study, published in PLoS Genetics, sequenced portions of the Y chromosome from 62 different men and found that it is prone to large scale structural rearrangements allowing “gene amplification” – the acquisition of multiple copies of genes that promote healthy sperm function and mitigate gene loss.

‘The study also showed that the Y chromosome has developed unusual structures called “palindromes” (DNA sequences that read the same forwards as backwards – like the word “kayak”), which protect it from further degradation. They recorded a high rate of “gene conversion events” within the palindromic sequences on the Y chromosome – this is basically a “copy and paste” process that allows damaged genes to be repaired using an undamaged back-up copy as a template.’ Sounds like more of a Kluge than a solution to me.

So, is the Y going the route of the dinosaurs? Is the ultimate cure for male baldness going to be the X chromosome? Opinion, fortunately is divided… probably along gender lines, but I can’t be sure, so don’t quote me. Anyway, if I were in charge of evolution, I’d like to think I wouldn’t have put all my eggs in one basket… actually, make that sperm. Why in the world would you put something as important as an SRY gene on a tiny little ticket that could end up in the wash? Why not shift it to another, bigger, more prestigious chromosome -one that could take care of itself in a fight or whatever? Apparently some rodent populations are experimenting with this, but not us. And, even more speculatively, if we did, we might end up as a new species according to Jenny Graves, from La Trobe University in Australia. Okay, I won’t go down that road, but it’s probably a good thing I’ve already retired as an obstetrician -I’d be out of a job… I’d maybe need new training as a vet or something.

And, it turns out that (blush), ‘the interesting thing about humans is that while the Y chromosome is needed for normal human reproduction, many of the genes it carries are not necessary if you use assisted reproduction techniques. This means that genetic engineering may soon be able to replace the gene function of the Y chromosome, allowing same-sex female couples or infertile men to conceive.’

Well, as long as my Y lasts, I intend to carry on wearing pants, and shaving, till death do us part. Whoops, I take that back…




Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this:
search previous next tag category expand menu location phone mail time cart zoom edit close