Difference between revisions of "Inbreeding depression"

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During settlement planning, if the [[human]] [[population]] is to [[sexual reproduction|reproduce]], careful consideration into the size of the starting population must be carried out. The size of the human population must not be too small due to the risk of '''Inbreeding Depression''' (causing genetic disorders) and it must not be too big due to the risk of [[overpopulation]] (causing lack of [[food]]/[[natural resources|resources]]).  
 
During settlement planning, if the [[human]] [[population]] is to [[sexual reproduction|reproduce]], careful consideration into the size of the starting population must be carried out. The size of the human population must not be too small due to the risk of '''Inbreeding Depression''' (causing genetic disorders) and it must not be too big due to the risk of [[overpopulation]] (causing lack of [[food]]/[[natural resources|resources]]).  
  
Dear Shakti,One can only wholeheartedly ensdroe the first part of your musings. Of late, the world has been caught in the maelstrom of an exponentially accelerating pace of change which has been so rapid and disorienting that it has clearly outstripped mankind's capacity to cope. Established shibboleths and power equations are constantly tumbling, and in the course of a single lifespan, one can see the old economic and social order being roiled as never before. Everyone – countries, governments, politicians, corporates, communities – is struggling to somehow maintain equilibrium, and to keep pace with ever-changing newly-emerging realities.On one plane, therefore, large sections of society are confronted with the new mores colliding with ancient wisdom and cultural signposts that were handed down since the ages and which signalled order and continuity. Old value systems are being rejected by the emerging younger generations. There are growing manifestations of anomie and angst that threaten to cause strife and social disorder. Established political systems are failing to cope with new socio-economic trends and realities, and Obama's speech that you referred to was but one manifestation of this.When it comes to the question of the connect between entropy and consciousness, however, I am not in complete agreement. I can do no better than to quote from  The Evolving Self  by the completely unpronounceable Mihalyi Cziksentmihalyi: The normal condition of the mind is chaos. Only when involved in a goal-directed activity does it acquire order and positive moods. It is not surprising that one of the worst forms of punishment is to place a person in solitary confinement, where only those survive who can discipline their attention without depending on external props. The rest of us need either an involving activity or a ready-made package of stimuli, such as a book or a TV program, to keep the mind from unravelling. It is therefore more likely that we will witness divergent trends in the evolution of thought and knowledge. Perhaps the majority are progressing towards increasing preoccupation with the mind-deadeningly trite and the inane, on the one hand, while a small percentage of thinkers, philosophers,  scientists, and intellectuals will unrelentingly focus on further building on the edifice of the ever-expanding storehouse of human knowledge.Permit me to digress a little. It is possibly a truism that engineers, scientists, and others of that ilk are most at ease in their respective comfort zones while dealing with deterministic certitudes. Consequently, there is always an ongoing endeavour to reduce even inherently non-deterministic concepts to mathematically definable probabilistic ones. The evolution of scientific thought has witnessed many inflection points. In the age of Newtonian physics, the order of nature appeared simple and relatively uncomplicated. Most observable phenomena could be easily explained in terms of a few clear-cut laws which appeared to be supported by the results obtained through observation and scientific experimentation. As we progressed along the path of knowing more and more about less and less, the neat and well ordered universe of Newtonian physics appeared to morph into a much more complex construct. For a while, Einstein's theories of relativity appeared to be that moment of epiphany which, for a while at least, could explain practically all of the observable phenomena.As man's never-ending quest for knowledge led to increasingly sophisticated and accurate visualisations and measurements both of outer space – the macro view of the universe – and of inner space – the realm of the nano-world of the submicroscopic – we are increasingly bumping against the boundaries of what can be explainable in terms of observable phenomena which can be verified experimentally. An interesting fall-out of this is the convergence between physics and metaphysics, most notably in fields like particle physics where some of the postulates almost border on the supra-natural – so far removed are they from the directly observable and experimentally verifiable.Let me quote Sir James Jeans, a famous British Astronomer: To-day there is a wide measure of agreement, which on the physical side of science approaches almost to unanimity, that the stream of knowledge is heading towards a non-mechanical reality; the universe begins to look more like a great thought than like a great machine.  Mind no longer appears as an accidental intruder into the realm of matter; we are beginning to suspect that we ought rather to hail it as the creator and governor of the realm of matter  not of course our individual minds, but the mind in which the atoms out of which our individual minds have grown exist as thoughts. Finally, in the context of Isaac Asimov's point on entropy, let us reflect on what Lincoln Barnett wrote in his book  The Universe and Dr Einstein :“Although it is true that the amount of matter in the universe is perpetually changing, the change appears to be mainly in one direction—toward dissolution .  The sun is slowly but surely burning out, the stars are dying embers, and everywhere the cosmos heart is turning to cold; matter is dissolving into radiation, and energy is being dissipated into empty space. “The universe is thus progressing toward an ultimate ‘heat death’ or, as it is technically defined, a condition of ‘maximum entropy’ . . And there is no way of avoiding this destiny.  For the fateful principle known as the Second Law of Thermodynamics, which stands today as the principal pillar of classical physics left intact by the march of science, proclaims that the fundamental processes of nature are irreversible.  Nature moves only one way.” So, whither is the human race headed? On the physical plane, we are likely to increasingly encounter and bump against the capacity of our infinitesimal slice of the universe to sustain us.At the same time, since man's thirst for knowledge will remain unquenchable, we will no doubt keep trundling towards the ever receding horizons of human knowledge. We are witnessing a growing convergence between hitherto two completely disparate strains of the evolution of thought, namely scientific thought on the one hand which is searching for the holy Grail of the one overarching theory which can explain everything, and on the other hand the spiritual search for the ultimate truth – the Ekam Sat.Will the twain ever meet?Cheers!Viney Sahgal '58( Lounge session group)
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==Cause==
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Statistically, every person owns 5 to 6 genetic defects, each usually only on one of two chromosomes in a pair, preventing clinical manifestation. The combination of two identical defective DNAs poses a 25% probability to result in a DNA with the same defect on both chromosomes, which inevitably causes some kind of disability.
  
 
==Possible solutions==
 
==Possible solutions==
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*Genetic screening and selection of the settlers who are going to [[Mars]]. If the settlers do not carry any genetic defect, the  inbreeding depression does not occur, no matter how small the population is. The problem is: Not all defects are known. Only a small number can be detected with today's knowledge, but that knowledge is supposed to increase rapidly in the next few years.
 
*Genetic screening and selection of the settlers who are going to [[Mars]]. If the settlers do not carry any genetic defect, the  inbreeding depression does not occur, no matter how small the population is. The problem is: Not all defects are known. Only a small number can be detected with today's knowledge, but that knowledge is supposed to increase rapidly in the next few years.
  
[[Category: Health]]
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[[Category:Psychology]]

Revision as of 13:32, 17 December 2018

During settlement planning, if the human population is to reproduce, careful consideration into the size of the starting population must be carried out. The size of the human population must not be too small due to the risk of Inbreeding Depression (causing genetic disorders) and it must not be too big due to the risk of overpopulation (causing lack of food/resources).

Cause

Statistically, every person owns 5 to 6 genetic defects, each usually only on one of two chromosomes in a pair, preventing clinical manifestation. The combination of two identical defective DNAs poses a 25% probability to result in a DNA with the same defect on both chromosomes, which inevitably causes some kind of disability.

Possible solutions

  • To achieve large genetic diversity a possible solution is to bring a few adult colonists and many fertilized human eggs to Mars. This gives an opportunity to build a big community on Mars with a comparatively small transport effort. (inspired by The Cascade)
  • Genetic screening and selection of the settlers who are going to Mars. If the settlers do not carry any genetic defect, the inbreeding depression does not occur, no matter how small the population is. The problem is: Not all defects are known. Only a small number can be detected with today's knowledge, but that knowledge is supposed to increase rapidly in the next few years.