Eternal Life

This seems a good subject for this weekend. But I’ve been pondering it ever since I read this in the January issue of National Geographic: “if you can live a few years more, there is a real chance you will never die, since mortality may be just a technical problem we solve.” Now as a 74 year old biologist, that caught my attention. Sure I’d like to see both houses of Congress controlled by Democrats, and see my granddaughter (currently 19 months old) graduate from college. But live forever?  

A bit of context: the statement I just quoted is part of a blurb written by Byron Reese to promote his new book which National Geographic saw fit to promote in its New Year edition. Yes, Byron is a young man – not a physician or biologist but a technocrat businessman and futurist. Reese’s book is entitled Infinite Progress: How the Internet and Technology will end Ignorance, Disease, Poverty, Hunger and War. And it seems - death. Heh, I’m for ending all five of those biggies that Byron says he can deal with; but since his book came out, ISIS, Boko Haram and Al Shabab seem to be using the internet and technology to head us in the opposite direction.  

But that’s not what I want to talk about in this blog. All sane people want to see the scourges listed in the book’s title go away. What I want to take issue with is the promise of ending death, the promise of eternal life. First, medical science should focus not so much on extending the life of elderly people as to tackling childhood diseases. I find it very painful to see images of children dying of cancer, their lives cut far too short.

I’ve already lived longer than both my grandfathers, and in another couple of years and I’ll have lived longer than both my parents. Modern medicine has given me better health in my seventies than it was thought possible a century ago. But live forever? – no way! 

Living things are designed to have a limited life span: some insects a day or two, some trees a thousand years. Amongst our ape cousins we humans have the longest lifespan, in part because of our extended childhood period leaving time for that big brain to develop. If in the next generation or so it is figured out how to extend life indefinitely  -  as a biologist I’m skeptical that it’s possible – then humanity would face an enormous moral crisis.

Generations pass on (it’s a good phrase) to make room for the next generations, not only physically and biologically but in terms of running our societies with new and better and more just ideas. If this medical breakthrough which Byron Reese predicts comes about it will be millionaires lining up to enjoy the expensive procedure while millions in Africa and Asia continue to die far too young. Furthermore, this planet is way overpopulated with humans as it is, driving many other species to extinction while being unable to feed all seven billion humans adequately. Curtail death and at some point we’d have to ban birth. 

I am extremely fortunate to be alive at this time in history. I feel the need to give back by helping people to appreciate the wonderful world of living creatures we have around us. In my very small way I vote and donate and advocate for a more just society. Then it will be time to move on, and younger and better generations can take the amazing story the next step.  To life! 

Simple humans

The acronym DNA and the word ‘gene’ are in common usage today but it was only in the 1940s that DNA was determined to be the genetic material, and DNA’s structure was not worked out till 1953. Then the race was on to find out how genes worked; a gene by definition being a stretch of DNA that codes for a particular substance. I had the great privilege to work on a small aspect of this in the early sixties for my PhD. In those days much of this work was done using bacteria for the simple reason that they have just one chromosome – a single thread of DNA. The bacterium that I worked with was a human pathogen called Pseudomonas aeruginosa. It gained a bit of notoriety around that time because it infected and killed the first heart-transplant patient; so I had to be careful. But my professor had chosen this species of bacterium because it had enzymes, and therefore genes, for digesting sugar in three different ways. We humans have just one way – the Embden-Meyerhof pathway. Pseudomonas had that plus two others. 

This was way before whole genomes came into the picture. It was assumed at that time that a bacterium would have about a thousand genes on its one chromosome. We hoped bacterial genomes would be fully elucidated one day, but doubted the human genome would be understood in my lifetime, and it was thought that it would probably entail mapping hundreds of thousands of genes. 

However, towards the close of the 20^thC estimates for humans were reduced to about 100,000 genes, a somewhat humbling figure seeing that E. coli had come out higher than originally expected with 4,485 genes on its single chromosome. Finally, with much fanfare involving President Clinton and Prime Minister Tony Blair a ‘rough draft’ of the human genome was announced in April 2000. What was not so widely publicized was that it was found that our genome only operated on about 30,000 genes. In 2012 I volunteered and had my entire genome sequenced, but even mine didn’t have any more. In fact in the few years since then, figures have been revised downwards so that latest estimates are closer to 20,000 genes, arranged on 46 chromosomes. 

But surely human beings are far more complicated and therefore require more genes on more chromosomes than other simpler creatures. Afraid not. Our ape cousins, chimps and gorillas, have 48 chromosomes, cows have 60, bears 74, and turkeys 80!  The gene count is even more humiliating: water fleas have 31,00 genes – fifty per cent more than we do; and even the simple Nematode worm, less advanced than the common earthworm, beats us with 21,000 genes. It’s even more humiliating when it comes to plants. Lowly mosses have around 32,000 genes, the cute little wayside flower Birdsfoot Trefoil has 40,000 and Poplar trees 45,000. 

There must be something wrong: how can this brilliant creature that’s put men on the moon, blown up islands with H bombs, polluted the planet to the extent that we’re buggering up the climate, and cut people’s heads off for not bowing to the correct god - how come we have so few genes?  Yeah, well.  

 

I'll leave you with a picture of cute little Birdsfoot Trefoil. But It takes twice as many genes to make this cutie which while pleasing us with its beauty above ground, does the amazing feat of fixing atmospheric nitrogen in its roots, thus enriching the soil for others.

Cousins

Folks uncomfortable with the implications of evolution often say that it means we’re descended from chimpanzees. Recently in one of our southern states, parents sued a biology teacher because she was telling her class that evolution was wrong and that the real truth as to our origins was in the Bible. In her defense in court the teacher said that she had never seen a chimpanzee turn into a human, which says something about teacher certification in her state.

Chimpanzees are my cousins. Very distant cousins. By definition one is not descended from one’s cousins but we share a common ancestor. My first cousins and I share common grandparents, either on my mother’s side or my father’s.  I have eleven first cousins and I am happy to say that I’m in touch with all eleven mostly thanks to Facebook. Some might therefore read this blog. As an only child I really appreciate my cousins. I’m pretty sure that I have seven second cousins, but I’m not certain of the number. Again, I am very happy that I keep in touch with three of these second cousins, again thanks to Facebook and e-mail. We share a great-grandparent.

I have no idea about any third cousins, although they must exist, where we share a great, great grandparent -  two greats.  In his book The Ancestor’s Tale (2004) Oxford University biologist Richard Dawkins estimates that we humans are approximately 250,000^th cousins of chimps, and our common 250,000 times great grandparents lived approximately six million years ago.

I share some facial similarities and even mannerisms with some of my first cousins. My second cousin Steve however is almost twice my height; and I’m sure if I did meet any third cousin we’d not be recognizably related, except by a DNA study. So those worried about evolution -  you are related to chimps but not that closely, unless it’s in comparison to some other creatures.  Go back not just six million years and a quarter of a million greats, but 340 million years and very approximately 175 million generations, and we find that we are cousins with all tetrapods (four-legged creatures), including those who’ve subsequently lost their legs like snakes and whales, or turned their front legs into wings like birds, or arms like us. We’re all cousins. Perhaps this is why some people are vegetarians.

What happened to global warming?

In the Boston area where I live we are getting pounded with snow leading to record accumulations and the inevitable quips ‘Whatever happened to global warming?’  I have been pondering my response to this for the last days when this morning my acquaintance Carolyn Johnson, science editor of the Boston Globe, has an excellent piece in the paper giving a detailed answer entitled ‘How warming can worsen snowfalls’. 

First, it is more helpful to use the term Climate Change rather than Global Warming, even though it is true that the basic thing that is happening to our planet is a warming due to substantially higher levels of CO2. As a result, the entire planet has warmed up 0.74*C ( 1.33 F) between 1906 – 2005. That doesn’t sound much. Tell most people and they just shrug and say ‘Huh, I’ll just wear a lighter shirt in summer and turn on the A/C more often.'

But think about that for a moment; 93% of that extra heat has been absorbed by the oceans. Think of the amount of extra energy it has taken to heat up the entire Atlantic and Pacific etc oceans. That energy is going to be expressed in various ways: stronger hurricanes and more energy in the jet stream, as well stirring a more aggressive arctic vortex in the winter. 

I first ran into this when researching the paper that I co-authored in 2012 with my colleagues Walter Kittredge, Elizabeth Wright and Donald Lubin entitled Changes in the vascular flora of the Middlesex Fells Reservation, Middlesex County, Massachusetts, from 1895 to 2011. Rhodora, Vol. 114, No. 959.  In our study of the plants of this forest reservation, four miles in from the sea, we did find that some cold-loving plants had disappeared and a few other species had come in from the south. But we found a more marked change in those that liked things wetter; for example a 10% increase in wetland species. When I studied weather reports for Boston I found that there had been an 8% increase in precipitation in the last hundred years, most of that increase in the last thirty years. ‘Precipitation’ includes both rain and snow, the latter being measured in special receptacles that melt the snow and then record the water content. If it’s fluffy snow, ten inches equals just one inch of rain. 

In the warmer months Rhode Island, Eastern Massachusetts and SE Maine get more rain because the prevailing winds from the south and south west are carrying more moisture.  An Atlantic ocean current comes south down the coast of New England carrying an increased quantity of cold water (along with damp cool air) because of the melting arctic ice cap. And these air masses tend to collide around the coast of Massachusetts. In the winter a more energetic jet stream also drags more arctic air our way.  All this adds up to heavier snow storms in the winter and more rain the rest of the year. But, because of global warming our winters (though intense) are going to get shorter. The local records being beaten this week in Boston are for amounts of snow in a limited period – a week or two weeks; but even this winter is unlikely to beat the winter-long record set back in the winter of 1995-96 when Boston got 107.6 inches (2.73 meters) of snow. 

So, I guess I’ll have to go and do some shoveling. But I’m encouraged by the belief that Spring is not that far away. 

And while we Bostonians complain about all the snow, climate change is having, and will have, far more serious consequences in other parts of the world such as Southern California, the Philippines, East Africa and certain Pacific island nations.

Mitochondria

In my last blog I talked a bit about mitochondria, and now they’re really in the news with the vote in the British House of Commons (equal to the US House of Representatives) to allow the use of another woman’s mitochondria when the intended mother’s mitochondria are in some way compromised leading to fatal disease in any child.

Of course we can expect to hear religious conservatives prattling on about meddling with God’s work. But even the press are using the term ‘a baby from three parents’.  Nonsense!

Dr Lynn Margulis, who until her death in 2011 was a professor at the University of Massachusetts at Amherst, was the pioneer of our understanding that in the early evolution of more complex forms of life certain bacteria got swallowed up into larger cells in what is now known and accepted as an extreme case of symbiosis: mitochondria as our energy ‘batteries’; and in plants chloroplasts for photosynthesis. These are microscopic organelles that have no say about me being a human as opposed to being a frog. And If you inject some chloroplasts from an oak tree into a rose bush it’s not then going to grow 80 feet tall and produce acorns! This British baby will be the child of its two parents’ gametes, just as I am.

Thanks to TV crime shows everyone has heard of DNA – deoxyribonucleic acid, a long thread like molecule that carries in the arrangement of it’s components the ability to make proteins. In the case of mitochondria there are a handful of genes specifically for making sugar metabolizing enzymes. With chloroplasts the little bit of DNA there controls the fabulous process of photosynthesis. But my mitochondria have had no say in making me a human being.  That happened when the nuclear DNA in the sperm from my father united with the nucleus in my mother’s egg cell. There’s no room for any mitochondria in the head of a sperm and so we get all our mitochondria from our mothers.

In 2002, Dr. Bryan Sykes of Oxford University published The Seven Daughters of Eve about the seven maternal lines of mitochondria amongst Europeans. Just seven. So in this British case, it will be pretty easy to find a donor with the exact same mitochondria as the mother.

We’re all happy to accept someone else’s blood when needed, provided it’s the same blood type of course. Same with mitochondria.  No genetic change, no ‘third parent’.  

Red blood cells carry oxygen to our cells. Once there the mitochondria use that oxygen to burn glucose to make energy - two organelles working in close cooperation. Let’s focus on the miracle of a new healthy baby made possible by these advances in medical science.