Let's imagine that you are made the administrator of an earth
like planet, devoid of human life, except your mining crew,
seeking for gold - not for ornamental value, but for environmental
saving uses.
You and your mining crew scanned the planets and found one
planet with copious amounts of gold. So you shoot
off into space from your homeworld and land on this planet, to
start mining operations.
But mining is back breaking work, so you decided to ask for more
miners, but the distance and time to provide more labour
is more difficult. Thus, with your knowledge of science, you
seek to manipulate the genetic structure of existing animals to
become the labourers to mine for gold.
In a few short years, you succeeded in altering the genes
of monkeys to your own genetic heritage, save for some codes which
you believe would not be necessary for mere labourers.
Your mining operations became more efficient and effective. In
time, your mining crew became supervisors, and then administrators
of regions on the planet to mine for more gold.
With the ability to create genetic mutants whom are in your
image, with only slight differences, the male and the
female species intermingle and intermarried, reproducing more
such 'mutants'.
Life becomes more complex later on, for the greed and power
lusts that resides in you, resides amongst your fellow mining
crew as well, and passed on to your mutants, and led to warfare.
wiping out majority of the leaders, even you.
The mutants continued on with life on their own, unthinkingly
but valuing and hoarding gold, not knowing its original
purpose, and formed civilisations of societies, based on
ancient knowledge passed down.
This is in summary, a brief one, of Sitchen's hypothesis.
He does have a convincing case, made up of archeological evidences
backed up with rigorous scientific discipline to explain
ancient data which may not had been myths, but actual reports
of what happened, based solely on a 'mutant' scribe's comprehension
and recording work.
This current generation already have the capability to
manipulate genes. We have the knowledge to 'terraform' inhabitable
planets to suit our needs. Our rocketry science is advancing beyond
fossil fuels to the realm of plasma engines. We....are the
descendants, or at least made in the image
of.....of........?