Posts Tagged ‘selective breeding’

14 baby pandas in one crib

September 24, 2013

Giant Pandas must be one of the most loved and yet most unsuccessful species ever. They have come to an evolutionary dead-end. They don’t seem particularly interested in their own survival either. They just don’t like to mate and eat only bamboo. They are not hunted by any predators but there are only some 2000 left in the wild. Apart from looking cute and cuddly they don’t play much part in any ecological balance. But these cubs are worth more than their weight in gold. A panda cub can be rented to a Western zoo for about $1 million per year.

Human “conservation” efforts seem to be focused on eradicating successful species and helping the unsuccessful ones. But pandas are incredibly cute.

14 pandas born between June and September 2013 at Chengdu Giant Panda Breeding and Research Base

BBC:

A group of 14 panda cubs have been put on display in China.

The 14 cubs were artificially bred in the Chengdu Giant Panda Breeding and Research Base in south-west China’s Sichuan province.

Born between July and September this year, they are currently being raised in two delivery rooms at the base.

The eldest, Meng Meng, is four times heavier than the youngest, Ya Yi.

On birth rates, abortions and “eugenics by default”

July 20, 2013

Selective breeding works.

Humans have applied it – and very successfully – for plants and animals since antiquity.

There is nothing “wrong” conceptually with eugenics for the selective breeding of humans. But the Nazis – and not only the Nazis – brought all of eugenics into disrepute by the manner in which they tried to apply the concept.  Because of the Nazis and the coercive treatment of some minorities in Europe and of the Aborigines in Australia where forced sterilisation, forced abortions, genocide, euthanasia and mass murder were used to try and control the traits of future generations, eugenics has come to be inextricably associated with the methods used. Even in more recent times genocide, mass rapes and mass murder have been evident even if not openly for the purpose of controlling the genetic characteristics of the survivors.

I note that evolution by “natural selection” does not intentionally select for any particular traits. Surviving traits are due to the deselection of individuals who have not the wherewithal to survive until reproduction. Natural Selection in that sense is not pro-active and evolution is merely the result of changing environments which causes individuals of a species who cannot cope with the change to perish. Evolution has no direction of its own and is just the result of who survives an environmental change. It is not not some great force which “selects” or  leads a species into a desired future. Species fail when the available spread of traits and characteristics among the existing individuals of that species is not sufficient to generate some individuals who can survive the environmental change. Natural Selection is therefore not an intentional selection process but represents the survivors of change. Of course, not all traits have a direct influence on survival. All “collateral” traits are carried along – coincidentally and unintentionally –  with those traits which do actually help survival in any particular environment. But as conditions change what was once a collateral trait may become one which assists in survival.

As breeding techniques go, “Natural Selection” relies on a wide variation of traits throwing up viable individuals able to cope no matter how the environment changes, while “Artificial Selection” chooses particular traits to promote but runs the risk of unwanted collateral traits showing up (as with some bulldogs unable to breathe or with the development of killer bees). Natural selection is the shot-gun to the rifle of artificial selection. The shot gun usually succeeds to hit the target but may not provide a “kill”. But the rifle usually kills but it could easily miss or even kill the wrong target!

Of all the babies conceived today about 1% are conceived by “artificial” means (IVF or surrogacy) and include a measure of genetic selection. Even the other 99% include a measure of partner selection and – though very indirectly – a small measure of genetic selection. A significant portion (perhaps around 20%?) are through “arranged” marriages where some due diligence accompanies the “arrangement”. Such due diligence tends to focus on economic and social checks but does inherently contain some “genetic selection” (for example by excluding partners with histories of mental or other illnesses in their families). If eugenics was only about deliberate breeding programs seeking particular traits then we would not be very far down the eugenics road. But more importantly around 20-25% of babies conceived are aborted and represent a genetic deselection. As a result, a form of “eugenics by default” is already being applied today.

(The rights and wrongs of abortion is another discussion which – in my opinion – is both needless and tainted. Abortion, I think, is entirely a matter for the pregnant female and her medical advisors. I cannot see how anybody else – male or female – can presume to impose the having or not having of an abortion on any pregnant person. Even the male sperm donor does not, I think,  warrant any decisive role in what another person should or should not do. No society requires that a female should get its approval for conceiving or having a child (with the exception of China’s one-child policy). Why then should not having a child require such approval? While society may justifiably seek to impose rules about infanticide, abortion – by any definition – is not the same as infanticide. Until the umbilical is severed, a foetus is essentially parasitic, totally dependent upon its host- mother and not – in my way of thinking – an independent entity. I cannot and do not have much respect for the Pope or other religious mullahs who would determine if I should shave or not or if a woman may or may not have an abortion).

Consider our species as we breed today.

In general the parents of children being conceived today share a geographical habitat. Apart from the necessity – so far – of the parents having to meet physically, it is geographical proximity which I think has dominated throughout history. Victors of war, conquerors, immigrants, emigres and wanderers have all succumbed to the lures of the local population within a few generations. In consequence, partners often share similar social and religious and ethnic backgrounds. But the geographical proximity takes precedence. Apart from isolated instances (Ancient Greece, the Egypt of the Pharaohs, the persecution of the Roma, European Royalty, Nazi Germany and the caste-system on the Indian sub-continent), selective breeding solely for promoting or destroying specific genetic traits has never been the primary goal of child-bearing. Even restrictive tribes where marrying outside the “community” (some Jews and Parsis for example) is discouraged have been and still are more concerned about not diluting inherited wealth than any desire to promote specific genetic traits.

But it is my contention that we are in fact – directly and indirectly –  exercising an increasing amount of genetic control in the selection and deselection of our offspring . So much so that we already have “eugenics by default” being applied to a significant degree in the children being born today.

Currently the global birth rate is around 20 per 1000 of population (2%), having been around 37 in 1950 and projected to reduce to around 14 (1.4%) by 2050.

Crude birth rate actual and forecast UN data

Crude birth rate actual and forecast: UN data

Of these the number conceived by artificial means (IVF and surrogacy) is probably around 1% (around 0.2 births per 1000 of population). For example for around 2% of live births in the UK in 2010 , conception was by IVF. In Europe this is probably around 1.5% and worldwide it is still less than 1%. But this number is increasing and could more than double by 2050 as IVF spreads into Asia and Africa. By 2050 it could well be that for around 3% of all live births, conception has been by “artificial” means and that there will be a much greater degree of genetic screening applied.

Abortion rates increased sharply after the 1950’s as the medical procedures developed to make this a routine procedure. Done properly it is a relatively risk-free procedure though there are still many “unsafe” abortions in the developing and religiously repressive countries. Since 1995 abortion rates worldwide have actually decreased from about 35 per 1000 women of child-bearing age to about 28 today.  These numbers would indicate that the number of abortions taking place today is around 20-25% of the number of live births.

http://www.economist.com/blogs/graphicdetail/2012/01/daily-chart-7

Global abortion rates: graphic Economist

Global abortion rates: graphic Economist

So of every 100 babies conceived around 25% are deselected by abortion and 75 proceed to birth. Only 1 of these 75 would have been conceived by “artificial” means. The genetic deselection by abortion is both direct and indirect. The detection of genetic defects in the foetus often leads to abortion and this proportion can be expected to increase as techniques for the early identification of defects or the propensity for developing a debilitating disease are perfected. In many cases abortion is to safeguard the health of the mother and does not – at least directly – involve any deselection for genetic reasons. In many countries – especially India – abortions are often carried out to avoid a girl child and this is a direct genetic deselection. It seems to apply particularly for a first child. The majority of abortions today are probably for convenience. But if the “maternal instinct” is in any way a genetic charateristic, then even such abortions would tend to be deselection in favour of those who do have the instinct.

The trends I think are fairly clear. The proportion of “artificial births” is increasing and the element of genetic selection by screening for desired charateristics in such cases is on the increase. The number of abortions after conception would seem to be on its way to some “stable” level of perhaps 25% of all conceptions. The genetic content of the decision to abort however is also increasing and it is likely that the frequency of births where genetic disorders exist or where the propensity for debilitating disease is high will decrease sharply as genetic screening techniques develop further.

It is still a long way off to humans breeding for specific charateristics but even what is being practised now is the start of eugenics in all but name. And it is not difficult to imagine that eugenics – without any hint of coercion – but where parents or the mothers-to-be select for certain characteristics or deselect (by abortion) to avoid others in their children-to-be will be de rigueur.


 

Fighting against species extinction is to deny evolution

February 27, 2013

I was reading an article today about the threat of extinction for leather-backed turtles and once again I started wondering as to why extinction of a species or a language or of an isolated tribe arouses moral outrage or is an emotional matter for so many people. I don’t want these turtles to become extinct just as I don’t want tigers or polar bears or pandas to become extinct. But this is purely an emotional reaction because each of these animals is attractive – to my human eye – in its own right. Outside of TV documentaries, zoos and safari parks I have never seen any of them. I don’t have the same reaction when I read that guinea worms or disease-carrying species of mosquitoes are being eradicated. “Good riddance” is then the predominating feeling that I have. Yet whether a mammal or a bacterium becomes extinct the genetic loss is about the same. That dinosaurs became extinct millions of years ago or even that humans killed off the dodo or the thylacine or the Javan tiger in more recent times arouses some feelings of regret but not any moral outrage or much emotional response from me. The article about the turtles – like most other articles about the extinction of species  – is permeated with the politically correct assumption that extinction would be a “bad thing”. But I never see properly addressed the question as to why the extinction of a species is a “bad thing”.

This is essentially a value-judgement and is taken for granted and yet – in the rational plane – I can only conclude that there is nothing “unnatural” about this. In fact it is this emotional desire that species considered “attractive” should not become extinct when their time is due that is irrational. Normal or natural evolution is always a result of change. It is the result of species responding to change where the individuals of a species most suited to the changed circumstances continue and reproduce. Where the variety existing within a species is insufficient to provide any individuals who can survive and reproduce in the changed environment, the species dies out. It is said that about 90% of all species that have ever lived have become extinct. If they had not there would be no room for the 10% that exist today. Just as homo sapiens would never have evolved without the environmental changes which led to the extinction of the dinosaurs, most of the species alive today would not have succeeded their extinct ancestors if conditions had not led to their extinction. Where a species cannot compete with another – in whatever the prevailing circumstances – it dies out. It makes room for the more successful species.

Siberian Tiger Français : Tigre de sibérie Ita...

Siberian Tiger Français : (Photo credit: Wikipedia)

So what then is the objection to – say – tigers becoming extinct which is not just an emotional reaction to the disappearance of a magnificent but anachronistic creature?  The bio-diversity argument is not very convincing and is of little relevance. To artificially keep an unsuccessful species alive in a specially protected environment has no genetic value. It increases the mis-match between the existing environment and the genetic profile needed to survive in that environment. In fact the biodiversity argument is only relevant for “life” in general and never for any particular species or group of species.  It can serve to maintain a very wide range of genetic material in the event of a catastrophe such that some form of life has a chance of continuing. But given a particular environment biodiversity in itself is of little value.

Returning to the tiger as an example, the variety of individuals within the tiger population does not provide any which have the characteristics necessary for adapting to the reality of co-existing with humans in some form of urban living. Foxes, on the other hand, are evolving within our lifetimes. In a few more fox generations, urban foxes will out-compete their “wild” cousins who may well become extinct. But urban foxes will thrive. Many bird species and insects are throwing up the individuals to succeed in the shadow of the success of the human species. Bacteria and no doubt viruses are also throwing up their survivors. Some bacteria are changing faster than we would like. The polar bears who visit Churchill every year are evolving. Those who know how to forage in human communities have a distinct advantage over their less intelligent brethren. And of those who visit Churchill it is the ones who avoid attacking humans which have the best chance of surviving. (Polar bears are of course thriving and are in no danger of extinction – but that is another story). Langur and rhesus monkey troops in Delhi are in the process of becoming urbanised and “evolving” to succeed in their human-filled environment. These species are not domesticated. They are still wild but they are evolving – by selection – into new species suited to their new environment.

All those species which succeed into the future will be those which continue to “evolve” and have the characteristics necessary to thrive within the world as it is being shaped and changed by the most successful species that ever lived (though we cannot be sure how far some particular species of dinosaur may have advanced). Putting a tiger into a zoo or a “protected” environment actually only preserves the tiger in an “unsuccessful” form in an artificial environment. Does this really count as “saving the species”? We might be of more use to the future of the tiger species if we intentionally bred them to find a new space in a changed world  – perhaps as urban tigers which can co-exist with man.

If a polar bear were to hunt and kill a seal – even if it was the last individual of a seal species – it could be a matter of some regret but it would not generate any moral outrage. And then if the polar bears did not themselves adapt to find alternative food sources – then they too would fail to survive. The loss of a species can always be a matter of some regret but so is the death of any individual. Both are equally inevitable but the regret is mitigated by what comes after.

The thought occurs to me that while there is no doubt that human activity is altering the environment for many species, it is of little benefit to try and deny evolution. Species protection must consist of helping “threatened species”  to evolve and not in standing-still in some artificial environment.

Perhaps the answer is – for example – to breed and train a new species of Siberian tiger to manage vast reindeer herds where they could also be allowed to hunt and devour a few!


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