Posts Tagged ‘genetics’

The New Eugenics

March 11, 2018

Eugenics, because of the way it was practised by the Nazis, has become a bit of a taboo word. But it has been practised in silence and by default for some time now.

ktwop (2013):

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.

As neonatal screening techniques improve, eugenics is no longer just by default but is increasingly due to an active choice being made. Down syndrome is already well on the way to being eradicated.



Why are Indian-Americans sweeping the US spelling bee?

May 30, 2014

I have watched the US spelling bee competition on TV a few times when visiting the US. For excitement and entertainment I would place it below the Olympics, the World Cup and a good cricket test match but above a 20/20 junket or the Eurovision song contest (which in recent times has just become ridiculous).

But there is something remarkable that is showing up. This year 6 out of the 12 championship finalists, and the top four, were of Indian origin.

The HinduIndian-Americans Sriram Hathwar of New York and Ansun Sujoe of Texas shared the title after a riveting final-round duel in which they nearly exhausted the 25 designated championship words. ………. The past eight winners and 13 of the past 17 have been of Indian descent, a run that began in 1999 after Nupur Lala’s victory, which was later featured in the documentary “Spellbound.”

American Bazaar:

…… although it’s an American competition open to students from all over the country, students of Indian origin have dominated the competition by a significant margin over the last several years. In fact, in both 2012 and 2013, all the top three contestants were of Indian origin.

From 2008-2013, the winner of the Scripps National Spelling Bee has been Indian American: Sameer Mishra, Kavya Shivashankar, Anamika Veeramani, Sukanya Roy, Snigdha Nandipati, and Arvind Mahankali. Since 1999, only five winners have not been of Indian descent, meaning 67% of winners over the last 15 years have been Indian.

Is the ability to spell then learned or is it genetic or both? From the manner in which Indian-Americans have swept this competition in the last few years, there is clearly some genetic component.

Spelling ability is not a measure of intelligence. But intelligence is a necessary – but not a sufficient – ingredient.  Excellent spelling ability as exhibited in the spelling bee competitions would seem to also need memory, drive, focus, education, supportive families and peers in addition. They also practice a very great deal.  A recent winner trained for 4 hours a day and a few thousand hours in total and committed some 100,000 words to memory. Spelling ability and reading skills are known to be linked but it is not too clear as to which depends upon which. Good spellers have been found in some surveys to be more organised than the “average”.

The Age: Kids who are good readers are often great spellers too, and now Australian scientists have uncovered a genetic explanation as to why. Researchers from Sydney, Melbourne and Brisbane tracked 650 sets of young twins to work out how much reading and spelling abilities are controlled by genes. 

The study found that the ability to read and spell were about 50 per cent inherited, with a child’s upbringing and schooling controlling the other half. But what was most remarkable, says University of Melbourne researcher Anne Castles, was the discovery that the same genes were involved in both activities. …… 

…… The scientists also evaluated the two main skills involved in reading – the ability to sound out words aloud and the ability to recognise words by sight that don’t follow the phonic rules, like “yacht”.

They discovered that these specific skills involved two distinctly different sets of genes, which explains why kids are often competent at doing one but not the other.

Poor spellers may be subject to a neurological deficiency. Lesions in the right brain which impaired some visual activity are known to have also causes spelling difficulties – a “spelling dyslexia”. It is also thought that personality traits have some connection to the ability to spell. It is thought that spelling ability is associated with a deep interest in language, its roots, in words and how they sound. Many good spellers make and use mental, visual representations of words.

There may not be a specific spelling gene, but genetics surely have a part to play.

Learn that word:

Why is a population that makes up roughly 1% of the US population so heavily represented at the event? 

1 –  The American school system and culture has a conflicted relationship with memory-based learning. Indian culture values academic achievement highly and values memorization as well, as a building block of higher-level knowledge. This, by the way, is also the reason why Indian Americans are not only dominating the Spelling Bee, but also produce much more than their statistical share of doctors, engineers and executives. 

2 –  Indian Americans/South Asians maintain tightly knit family and social communities, and place a paramount value within their community on academic performance. Social expectations around academic performance tend to be much higher than in other demographic groups. Academic success therefor has a big social pay-off.

3 –  Last but not least, the success at Spelling Bees is fostered by various initiatives that exclusively support Indian American/South Asian students. NorthSouth Foundation and the South Asian Spelling Bee are both set up to support the Indian American/South Asian community of aspiring champions. 

It’s great to win the first prize at the Scripps National Spelling Bee by competing with 10 million students for over $40,000 in prizes. There is certainly more incentive to dedicate the thousands of hours of intense study needed knowing that you can also apply these skills at the South Asian Spelling Bee, where you compete with just a few thousand other kids for a $10,000 first prize. 

“Animal conservation” in zoos is anti-evolutionary and probably immoral

February 27, 2014

The case of Marius the giraffe murdered recently at Copenhagen Zoo has led to more attention to the function of zoos, their supposed “conservation” efforts and their breed-and-cull policies. There is an aura of “goodness” around “animal conservation” which is quite unjustified. As practised today, animal conservation in zoos is anti-evolutionary and borders on the immoral.

I enjoy visiting some zoos (though there are many which are merely collections of psychotic animals) and I enjoyed taking my children to some zoos. It was primarily for entertainment and – as with all entertainment – offered some opportunities for learning. But I cannot subscribe to the politically correct notion that zoos are places where some animal species are being “saved” from extinction. At best they are places where some species, which are on the verge of extinction because they have failed to adapt or evolve to cope with their environments, are frozen into an artificial existence in quite unsuitable habitats for the purpose of entertaining visitors. Such species are not helped to change – genetically or otherwise – to be able to survive by themselves in a changing world. Conservation is taken be a “good thing” but consists only of preserving the animals and their current genes. If left to themselves they would still fail to survive. The animals are bred and over-bred such that healthy specimens must then be culled. That is stagnation not evolution. Zoos are just places for human entertainment and very little else – and there is nothing wrong with that. But they do not deserve any halo of “goodness” for their “conservation”.

To truly help a species to survive requires helping them to breed and evolve such that their survival characteristics are improved. But “conservation” today consists of creating living fossils which are incapable of surviving without human intervention. It is taking a frozen snap-shot of the species and its genes. That is fundamentally anti-evolutionary. I have written on this theme before (Genetic adaptation not stagnating conservation is the way to help threatened species),

Conservation – as stagnation – is not sustainable.  Trying to prevent change is a futile exercise. It is change which is the fundamental characteristic of life. It is managing change and even designing change which is a particular strength of the human species. It is human ingenuity at work. It is time to give thought to how we can help the species around us evolve into the neo-species which can cope with the changes which are inevitable.

This BBC article today only reinforces my view that so-called “animal conservation” in zoos is just show business and has nothing whatever to do with helping endangered species to survive.

How many healthy animals do zoos put down?

When Copenhagen Zoo put down a healthy male giraffe earlier this month, much of the world was horrified. But those in the know say it’s quite normal – a fate that befalls thousands of zoo animals across Europe every year. ….. 

It’s often hard to get any information, but the 340 zoos that belong to the European Association of Zoos and Aquaria (EAZA) must sign up to the organisation’s various breeding programmes, and for each species in the programme there is a studbook – a kind of inventory which records every animal’s birth, genetic make-up, and death.

EAZA does not publish these records or advertise the number of healthy animals that have been culled, but executive director Dr Leslie Dickie estimates that somewhere between 3,000 and 5,000 animals are “management-euthanised” in European zoos in any given year. …… 

…….. Four German zookeepers were also prosecuted in 2010 for culling three tiger cubs at Magdeburg Zoo “without reasonable cause” (though the EAZA judged the step “entirely reasonable and scientifically valid“). ….

… The EAZA Yearbook 2007/2008 (the latest publicly available edition) states clearly that a “breed and cull” policy should be followed for some animals, like the pygmy hippopotamus.

Surpluses are a problem with a number of species, including monkeys and baboons, it notes. ….



I am but a prisoner of my genes

January 20, 2014

I’d like to fly but but my genes don’t agree

And they determine how tall I will be,

I am but a lowly prisoner of my genes,

My apparent freedom is not quite what it seems.

But thanks to my genes I’m not a chimpanzee.

All abnormal behaviour is illness, says DSM-five,

Just following precisely what our genes do contrive.

Our genomes hold us tightly captive,

As slaves in their battle to survive,

So it matters not how much we strive.


You are not just your genes, you are how they are expressed

December 8, 2013

As genetics advance it is becoming clear that an individual’s genes are only a part of the story. The same genes may be expressed in many different ways. And how a gene or a group of genes are expressed depends upon environmental and other triggers which are yet to be fully understood. Your genes may be your blueprint but you are what the manufacturer then produces depending upon the materials and resources available to him. In fact “blueprint” may not be the best analogy since a “blueprint” today may well even define the method of manufacture to be followed and the materials to be used. A set of genes being a “pattern” to follow may be a better representation. How the pattern is read and put into effect then determines the final product.

David Dobbs has an interesting article about how the simplistic view of the all-determining gene is changing.

… The grasshopper, he noted, sports long legs and wings, walks low and slow, and dines discreetly in solitude. The locust scurries hurriedly and hoggishly on short, crooked legs and joins hungrily with others to form swarms that darken the sky and descend to chew the farmer’s fields bare.

Related, yes, just as grasshoppers and crickets are. But even someone as insect-ignorant as I could see that the hopper and the locust were wildly different animals — different species, doubtless, possibly different genera. So I was quite amazed when Rogers told us that grasshopper and locust are in fact the same species, even the same animal, and that, as Jekyll is Hyde, one can morph into the other at alarmingly short notice. 

Not all grasshopper species, he explained (there are some 11,000), possess this morphing power; some always remain grasshoppers. But every locust was, and technically still is, a grasshopper — not a different species or subspecies, but a sort of hopper gone mad. If faced with clues that food might be scarce, such as hunger or crowding, certain grasshopper species can transform within days or even hours from their solitudinous hopper states to become part of a maniacally social locust scourge. They can also return quickly to their original form.

In the most infamous species, Schistocerca gregaria, the desert locust of Africa, the Middle East and Asia, these phase changes (as this morphing process is called) occur when crowding spurs a temporary spike in serotonin levels, which causes changes in gene expression so widespread and powerful they alter not just the hopper’s behaviour but its appearance and form. Legs and wings shrink. Subtle camo colouring turns conspicuously garish. The brain grows to manage the animal’s newly complicated social world, which includes the fact that, if a locust moves too slowly amid its million cousins, the cousins directly behind might eat it.

How does this happen? Does something happen to their genes? Yes, but — and here was the point of Rogers’s talk — their genes don’t actually change. That is, they don’t mutate or in any way alter the genetic sequence or DNA. Nothing gets rewritten. Instead, this bug’s DNA — the genetic book with millions of letters that form the instructions for building and operating a grasshopper — gets reread so that the very same book becomes the instructions for operating a locust. Even as one animal becomes the other, as Jekyll becomes Hyde, its genome stays unchanged. Same genome, same individual, but, I think we can all agree, quite a different beast. ….

…. Gene expression is what makes a gene meaningful, and it’s vital for distinguishing one species from another. We humans, for instance, share more than half our genomes with flatworms; about 60 per cent with fruit flies and chickens; 80 per cent with cows; and 99 per cent with chimps. Those genetic distinctions aren’t enough to create all our differences from those animals — what biologists call our particular phenotype, which is essentially the recognisable thing a genotype builds. This means that we are human, rather than wormlike, flylike, chickenlike, feline, bovine, or excessively simian, less because we carry different genes from those other species than because our cells read differently our remarkably similar genomes as we develop from zygote to adult. The writing varies — but hardly as much as the reading.

This raises a question: if merely reading a genome differently can change organisms so wildly, why bother rewriting the genome to evolve? How vital, really, are actual changes in the genetic code? Do we even need DNA changes to adapt to new environments? Is the importance of the gene as the driver of evolution being overplayed?

I think the idea that anything drives evolution is the wrong end of the stick. Evolution is a result of response to change. The resultant evolution is by deselection of those individuals who cannot survive the change – it is not a pro-active selection of desirable traits for some change yet to come.

So it seems to me that it is perfectly logical that a set of genes only describe and define an envelope of possibilities. It is gene expression which then – reacting to environmental or other triggers – determines the particular model from within the envelope that will materialise. But the set of genes are still critical in that they set the constraints – they define the envelope of possibilities. And no matter how creatively they are expressed, the constraints and the envelope still apply. I suspect that we have only just begun to understand the incredibly wide variation that gene expression permits with any given set of genes and how such expression can be triggered.

This variability is sufficiently wide that one twin can be a saint and the other can be a sinner but this variability is not so great that we can suddenly morph into chimpanzees.


Genetic adaptation – not stagnating conservation – is the way to help threatened species

October 26, 2013

If the big cats, or elephants or giraffes or pandas want to survive into the distant future they need to evolve. The changes taking place in their environment and in their loss of habitat are happening too fast for natural selection to throw up the genetic changes needed for long term survival. As long as humans remain the dominant species in their environment they will need to come to terms with that – genetically. Conventional conservation efforts are fundamentally flawed. They are backwards looking. They try to preserve these species – as they are – in artificially protected habitats which are frozen in time, which remain unchanged while the world around them changes. Conservation attempts to freeze these species and thereby lock them into the non-viable position they have found themselves in. This is not going to help them to continue into the future, except as an unsuccessful species. It is paradoxical that unsuccessful species are subject to conservation efforts and successful species get labelled as pests.

Much of the rapid change to the environments for these species is a consequence of the success of humanity as a species. Trying to keep a species unchanged and stagnating in a changing world seems to me to be irresponsible. And creating  little protected bubbles of habitat – whether in a reserve or a zoo can only be a short term measure. Domesticated animals are at little risk of extinction as long as humans thrive. Their success is inextricably linked with the human species and they have been adapted genetically to be what they are today. They are not allowed to breed freely or indiscriminately and that is the genetic price they pay. But their survival is assured – at least as long as humans thrive and maybe even beyond.

‘There are many more “urbanised” species which have through a natural – but environmentally coerced or forced – selection adapted genetically to have the traits which allow them to be successful in  the human-dominated environments they find themselves in. Foxes, bears, wolves, badgers and even the polar bears of Churchill have evolved and adapted to survive in human dominated environments. But they generally live surreptitious lives in the shadow of man. They have not found a sustainable position  as yet. An increasing number of birds have adapted their behaviour (presumably also by genetic changes) to take advantage of human behaviour. They have learned to live in and around our cities, to take advantage of our agricultural and harvesting habits and to use our waste streams as their food source. Even in the water, there are fish species which succeed because of the changes brought about by man. Many insects – be they cockroaches or spiders or mosquitoes, or termites – now know how to take advantage of man-made environments. At the microbial or viral level, species are not much concerned by the changes wrought by humans and continue their merry way.

Now in this new age of DNA analysis and intentional selection of genes I think it is time for Conservation to move away from merely trying to “freeze” species in an artificially protected environment and to move into a pro-active phase where humans actually help threatened species to continue into the future. This does not mean that the neo-species that appear must necessarily be domesticated or in the service of humans but it does mean that they must share the same habitat and be able to co-exist. If they require a specialised habitat which is likely to disappear or change due to man or for any other reason, they are destined to eventually go extinct. Putting such species into zoos or other artificially maintained or otherwise protected habitats only preserves an obsolete species in a temporary environment. Conventional conservation as it is practiced today goes down that route. And while it may provide a short term method for preserving the genes of such species, it is in an unsustainable form. It is a method which does no real service to such species.

Instead of trying to recreate the woolly mammoth for an environment which is totally unsuitable or of making futile attempts to preserve habitats for elephants so that they continue “unchanged”, it would be better if we considered how elephants – or the big cats – could be assisted along the evolutionary path such that they could find a natural and sustainable place in the brave new world that they now inhabit. For example, if neo-elephants were helped to evolve genetically such that their propensity to wander over very large areas reduced, or if they preferred certain kinds of trees and bushes and left others alone, or where their wanderings were more discerning and not as damaging to human crops, then herds of neo-elephants could find a sustainable place by the side of humanity.

Perhaps Siberian neo-tigers could be evolved genetically to help herd reindeer and develop a mutually beneficial partnership with man. An occasional reindeer kill would then be quite acceptable. It would be so much more contructive if neo-wolves were helped not to stagnate genetically, but instead to evolve the behavioural characteristics that allowed them to find a way of co-existing with humans and human flocks of sheep. The idea of neo-dolphins who communicate with man and have a herding behaviour in the oceans which benefit both humans and themselves has long been a subject of science fiction. Our nearest primate cousins have to be helped to move on and not to stagnate into extinction. The pace of environmental change is much too fast for natural selection to throw up the individuals capable of survival. Instead a natural deselection of individuals incapable of surviving is taking place. Neo-gorillas and neo-chimpanzees will not appear without human intervention.

Conservation – as stagnation – is not sustainable.  Trying to prevent change is a futile exercise. It is change which is the fundamental characteristic of life. It is managing change and even designing change which is a particular strength of the human species. It is human ingenuity at work. It is time to give thought to how we can help the species around us evolve into the neo-species which can cope with the changes which are inevitable.


Nutrition rather than genetics when it comes to height over the last 100 years

September 2, 2013

Nutrition – and especially nutrition in the early years of life – has dominated the development of human height over the last 100 years. An average growth of 11 cm in the last 100 years. One hundred years is just over 5 generations and far too short a time for Darwinian genetics to have had any significant impact. This increase in height, rather than being hampered, actually accelerated during 2 World Wars and the Great Depression in the 15 European countries studied.

But now as the height impact of improved nutrition plateaus, perhaps the next 100 years and five generations of fast food will bring an 11cm increase in human width!!

In the “nature” versus “nurture” debate it only convinces me further that for all genetic traits, the particular set of genes in an individual only provides a Bell curve of the available framework for the expression of that trait. And there will be a Bell curve for each “trait” which is genetically determined. Thereafter it is “nurture” and/or the existing environment which determines the level to which that trait is expressed.

Nature and Nurture

Nature and Nurture

Science Codex: 

The average height of European males increased by an unprecedented 11cm between the mid-nineteenth century and 1980, according to a new paper published online today in the journalOxford Economic Papers. Contrary to expectations, the study also reveals that average height actually accelerated in the period spanning the two World Wars and the Great Depression.

Timothy J. Hatton, Professor of Economics at the University of Essex and the Research School of Economics at Australian National University in Canberra, examined and analysed a new dataset for the average height (at the age of around 21) of adult male birth cohorts, from the 1870s to 1980, in fifteen European countries. The data were drawn from a variety of sources. For the most recent decades the data were mainly taken from height-by-age in cross sectional surveys. Meanwhile, observations for the earlier years were based on data for the heights of military conscripts and recruits. The data is for men only as the historical evidence for women’s heights is severely limited.

Professor Hatton said, “Increases in human stature are a key indicator of improvements in the average health of populations. The evidence suggests that the improving disease environment, as reflected in the fall in infant mortality, is the single most important factor driving the increase in height. The link between infant mortality and height has already been demonstrated by a number of studies.” Infant mortality rates fell from an average of 178 per thousand in 1871-5 to 120 per thousand in 1911-15. They then plummeted to 41 in 1951-5 and 14 in 1976-80.

In northern and middle European countries (including Britain and Ireland, the Scandinavian countries, Netherlands, Austria, Belgium, and Germany) there was a “distinct quickening” in the pace of advance in the period spanning the two World Wars and the Great Depression. This is striking because the period largely predates the wide implementation of major breakthroughs in modern medicine and national health services. One possible reason, alongside the crucial decline in infant mortality, for the rapid growth of average male height in this period was that there was a strong downward trend in fertility at the time, and smaller family sizes have already been linked with increasing height.

Other factors in the increase in average male height include an increased income per capita; more sanitary housing and living conditions; better general education about health and nutrition (which led to better care for children and young people within the home); and better social services and health systems.

Source: Oxford University Press


The return of Eugenics

March 30, 2013

It is the association of the practice of Eugenics with Adolf Hitler and his Nazis and the stigma which that brings which makes it – at least overtly – politically incorrect and tabu. But it was formally practiced by many governments through the 1900’s and as late as 1975 in Sweden.  But Hitler was also a vegetarian, a teetotaler and a non-smoker. So something more than a “Hitler connection” is needed when discussing eugenics. This recent tweet from Richard Dawkins  together with all the recent developments in genetics and IVF and pre-natal screening got me to wondering as to why there is a perception in some quarters that eugenics is “evil”.

Richard Dawkins@RichardDawkins  “Eugenics”: What’s wrong with a nonrandom choice of a gene your child COULD have got from you at random, anyway, by normal genetic lottery? 9:18 AM – 17 Mar 13

Definition oeugenicsnoun [treated as singular]

the science of improving a population by controlled breeding to increase the occurrence of desirable heritable characteristics.

The application of eugenics included genetic screening, birth control, promoting differential birth rates, marriage restrictions, segregation, compulsory sterilization, forced abortions or forced pregnancies and genocide. But the history of the practice of eugenics goes back to infanticide in pre-historic times and we apply it every day without any objections in the management of domestic and wild animals. In the days when we were hunter gatherers – it is thought – infanticide was commonly prevalent:

Joseph Birdsell believed that infanticide rates in prehistoric times were between 15% and 50% of the total number of births, while Laila Williamson estimated a lower rate ranging from 15% to 20%. Both anthropologists believed that these high rates of infanticide persisted until the development of agriculture during the Neolithic Revolution. Comparative anthropologists have calculated that 50% of female newborn babies were killed by their parents during the Paleolithic era. Decapitated skeletons of hominid children have been found with evidence of cannibalism.

The Hitler and the Nazi connotation is certainly part of it but is it primarily the application of coercive measures which today gives eugenics its unsavoury reputation? As practiced in the early 20th century eugenics was applied to humans pretty much as it was for animals – effectively by promoting certain types of matings, preventing others and culling unwanted individuals. I suspect that it is not just the Hitler connection and the coercive treatment of humans which is so objectionable but also that groups of humans were treated en masse as animals for the sake of improvement of the herd.

In today’s world it is perfectly acceptable for couples using IVF to choose – so far as is possible – desirable genetic characteristics of the sperm or egg donor or both. Genetic pre-natal screening can and does lead to abortions if certain criteria are met or others are found wanting. It is effectively culling before birth. Potential surrogate mothers are genetically screened before selection. Genocide and mass rape still take place in conflict situations (Kosovo, Rwanda…) but are universally condemned. We find it perfectly acceptable however that these choices be made by individuals or couples about “their” child. It is taken to be a proper expression of individual rights – though the consequences are mainly borne by the child yet to be born (or not born). But we would find it quite unacceptable today if any government or society would impose these choices on any individual.

It would seem therefore that eugenics is here to stay. As a preventative health measure it is already acceptable if practiced voluntarily by the individuals involved. Selective breeding practiced voluntarily by individuals is also acceptable but is unacceptable if imposed by coercive decree. Enforced sterilisation of those considered mentally or physically defective was a major part of the Eugenics programs in Europe and the US and Australia but the sterilisation of the mentally ill is much rarer now. It seems inevitable that as physical or behavioural or mental characteristics can be connected to specific genes or groups of genes that these characteristics will become part of the criteria for selecting sperm or eggs or for continuing with a pregnancy or not. And even if “voluntary” individual eugenics is already in place today, I am afraid that it is not unthinkable that governments and societies will once again insist on specifying the criteria to be used to improve the common condition. I conclude therefore that it cannot be eugenics which is evil but it is the manner in which it is practiced which can.


European Gypsies (Roma) descended from the ancestors of NW Indian Adivasis

November 30, 2012

While the Indian origin of the European Roma populations is linguistically and genetically well-established, accurate identification of their South Asian source has remained a matter of debate. A new open access paper PLoS ONE 7(11): e48477. doi:10.1371/journal.pone.0048477 now pinpoints the ancestry of today’s Roma to the ancestors of the Adivasi (“original people)  tribes of North West India.

The Phylogeography of Y-Chromosome Haplogroup H1a1a-M82 Reveals the Likely Indian Origin of the European Romani Populations, Niraj Rai et al.

I note , in passing, that the discrimination and “oppression” of the current Roma populations across all of Europe is not so unlike the discrimination and “oppression” being suffered by their distant cousins who are the current Adivasis in India.

Out of India Migration Rai et al



What is evolutionary selection now selecting for?

November 14, 2012

What are the genetic characteristics that are effectively being “selected for” today?

Evolutionary selection is a result not a cause. It is a result describing the genetic change of a population not of an individual. But all genetic change in a population comes about only through the procreation of new generations of individuals.

Evolution then is the result of the survival, success and reproduction of organisms within an environment which is changing. By environment I mean all surrounding factors whether geologic or climatic or of competition within the species or with other species. In a population of organisms the relative success of and subsequent reproduction of those better suited to the environment begets a gradual change in the  characteristics of the surviving organisms.  It is because of the environmental changes in the first place that there is a subsequent change in the characteristics of the organism best suited to that environment. It is this gradual change of the surviving characteristics that we call evolution and we say that the resultant, surviving characteristics have been “selected for”. If the environment did not change and if an organism was suited to its environment, the genetic make-up of the organisation would always tend back to its stable equilibrium position. Any mutational changes would provide no benefit and would just die away. Without environmental change there would be no evolution to report. Over long stretches of time and many thousands of generations, these gradual changes of environment have been sufficient to have created all the species of living things that have ever existed and to have eliminated all the non-viable species that have gone extinct.

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