[IzzieC (OP)]

Mike asks

Many people believe that ALL mankind descended from the original human pair as stated in scriptures, but if that were true it would not be possible to have DNA showing differences like Denisovan, Neanderthal etc. What would human DNA science be like on earth if life emerged from only one human pair?

Can you help?

[atbsphotography]

I would assume if there is just a single couple who populated the earth then the resulting DNA of that pair would need to evolve to rid itself of genetic mutations within the chromosomes and thus ending up with no mutations in the resultant offspring of the pair.

As we already know interbreeding does carry the risk of genetic mutations and early death or the pair having a stillborns/ severely disabled children.

Another interesting fact aside is that if the world was populated by just two people then the population of earth would take a lot longer to climb to the point it is today. Also if both parents happened to be of one colour the early generation would have to evolve over the years to be another colour or by way of a genetic mutation.

[evan_au]

ALL mankind ... Denisovan, Neanderthal

These groups are distinct in their own DNA, and Neanderthals are distinguishable from their skeletons (we don't have enough of a Denisovan skeleton to tell what they looked like).

So these were not homo sapiens, but were close-enough distant relatives to interbreed with them.

ALL mankind descended from the original human pair

There is genetic evidence of several "population bottlenecks" that have happened in human (and pre-human) history, with some events involving as few as 70 individuals.

Not quite as severe as two individuals.
See: https://en.wikipedia.org/wiki/Population_bottleneck#Humans

[puppypower]

Mike asks

Many people believe that ALL mankind descended from the original human pair as stated in scriptures, but if that were true it would not be possible to have DNA showing differences like Denisovan, Neanderthal etc. What would human DNA science be like on earth if life emerged from only one human pair?

Can you help?

The bible is describing changes in the human mind, which then impacted evolution via natural selection. Selective advantage is not only genetic dependent, but also environmental dependent. Long thick warm fur; genetic based, will be selected in the Arctic region, but not at the Equator. Environment has the final say.

The timing in the bible; Genesis, connected to Adam and Eve, coordinates with the invention of written language, which was critical to the first stable civilizations. Stable civilization, in turn, created a stable artificial environment that changed the parameters for human natural selection, into something that was not natural to the earth.

As an example, when the pre-humans were migratory hunters and gatherers, there may have been a selective advantage being able to find and gather food, while eating on the move. Civilization allowed the invention of farming, which altered the parameters of natural selection, in terms of gathering food, Now selective advantage for gathering was seasonal and stationary. When the tractor was invented, selective advantage for gathering became connected to tractor driving and not hand picking. There is a drift in selected DNA.

It will not take long before the entire community starts to alter itself, in terms of the needs of social advantages; reward, which then impacts breeding and selective advantage.

Computers, for example, were around in 1980's, but were somewhat hard to use and were limited to offices and colleges. Computer based environments and selective advantage was limited to smaller coves. Now, selective advantage, connected to computer usage, is world wide in 30 years. This impacts natural selection in terms of resources; reward and breeding rights.

Since Adam and Eve were connected to changes in the mind, even social memes, which are like software virus, can impact the entire population, altering group agreed, selective advantage parameters, thereby funneling genetics. For example, laws that allowed a male to have many wives, versus later laws that only allow one wife, each impact the global genetic direction, differently. 

Epigenetic played a role in terms of the Adam and Eve affect. Epigenetic changes are connected to post modification of genetic expression. This is subject to will power and choice. This does not change the genes on the DNA, but it does impact how the genes are expressed. In terms of altering natural selection, a new skill can be acquired through creative propensity and practice; writing, which makes epigenetic changes in one person. Their output; actions, allows others to watch and copy, until the social environment assembles itself, instituting the new selective parameters; everyone does the new dance move to be cool.

[puppypower]

There is a tendency in science to look at only a natural explanations for modern human evolution. However, willpower and choice can alter the parameters behind any natural explanation. For example, the American Bald eagle was hunted to near extinction. In 1963, there were less than 500 nesting pairs left. This was caused by humans changes to the environment, such as inventions like guns and human choices like sport bird hunting. Decades later, humans altered the social and physical environment to allow the eagles to make a come back. Eagle evolution was made different based on human parameters, mixing with natural selection. 

A better example, are dog breeds. Say we were space explorers, who reach the earth, but who did not know that humans artificially selected dog breeds, to create over a hundred distinct genetic breeds. Instead, we use the traditional natural selection and genetic arguments, without regard to any human willpower and choice. How long would it take for this many dog breeds, to stem from one common genetic ancestor; wolves? Would it be millions of years, instead of 100 years.

The natural path would be explained with random assumptions and slow boat logic. The Adam and Eve affect was connected to willpower and choice, apart from natural instincts, which can speed up and/or slow down, the natral selection process.

Consider royalty and the philosophy of cultural purity. A royal bloodline is not based on natural selection. Selection is decided many years in advance, even for future generations. Since the kings own everything, he can pass this on, without any competition. We can all pretend this is natural or maybe divine selection. This is not natural and will create a false sense of natural genetic focus and lack of drift. 

The problem with evolutionary theory, is atheism competes with religion, and religion has a copy right on advance evolutionary theory that includes the impact of willpower, choices leading to epigenetic inductions, and social memes acting as imperatives for the environment. These can all alter the natural course of events.

For example, if you look at world wide population growth, culture allows that speed to increase, much faster, than natural, since artificial choices can alter the natural checks and balances. What is the impact of abortion on natural selection?

[CliffordK]

Homo Sapiens and Neanderthals apparently were genetically compatible, and could interbreed.  At least that is what the current theory is, thus increasing our genetic diversity somewhat, at least for some humans.

However, at some point in our evolution, there was a chromosome 2 fusion.

https://en.wikipedia.org/wiki/Chimpanzee_genome_project
https://en.wikipedia.org/wiki/Chromosome_2#Evolution

The chromosome 2 fusion likely led to an extremely tight bottleneck in human evolution, perhaps down to a single breeding pair (or perhaps brothers and sisters). 

They may have been able to interbreed with the previous generation, but likely produced sterile offspring (think donkeys breeding with horses to produce sterile mules). 

[puppypower]

All members of Hominidae except humans, Neanderthals, and Denisovans have 24 pairs of chromosomes.[7] Humans have only 23 pairs of chromosomes. Human chromosome 2 is a result of an end-to-end fusion of two ancestral chromosomes.[

There is a logical way to explain this progressive change; directional evolution. DNA is the most hydrated molecule in the cell. The DNA, due to its composition and large size, has the most total chemically bound water; will not centrifuge off.

If we fused two chromosomes, the net result is that even more water becomes chemically bonded to one even bigger molecule. This is an expected result, when evolution occurs in water. Water is not easy to change and is driving the DNA in a direction that minimizes the potential of the DNA in water.

What that change then does, is lower the water potential within the nucleus. The larger chromosome adds less potential to the nucleus water than before. This then changes some of the active and inactive packing configurations, and can enhance new sweets spots, so new things can start to happen.

The starter codons on coding genes, are rich in adenine. Adenine is used because these moieties have the highest free energy content, relative to water. Synthesis of adenine from scratch is endothermic. Adenine is hot spot in water. They stand out in the nucleus and are easy to find by enzymes; through water signals and finger prints.

The fusion of two chromosomes will lower the background potential of the nucleus water, slightly, and make starter codons even more pronounced. This also makes less predominant genes look bolder, for subsequent cellular trial and error and R&D. Change quickens.

The most logical place for this to occur would have been within the ovum of a transition female. This induction can be done via what I like to call configurational potential. The ovum contains all the materials needed to make a large number of daughter cells. All this high energy and low energy material has an impact on the water. This is a good time to use the leverage of this bulk material, to tweak the nucleus water potential, which then tweaks a needed change in the DNA to lower the potential.