Thursday, August 24, 2006

Brain Gene Could Explain Why Yours is So Big #2

Brain Gene Could Explain Why Yours is So Big, Livescience, Ker Than, 16 August 2006 ...

[Graphic: "Brainpower boost: the human brain (top), which is bigger and more complex than a chimp's (bottom)," ScienceNOW.

Continued from part #1.]

The majority of these so-called "human accelerated regions," or HARs, were located near genes that help regulate the function of other genes. [As the article says further down (see part #3 when posted), this particular HAR1F gene does not code for proteins but RNA. So presumably this non-protein coding region, was part of what was previously dismissed by Darwinists as "junk DNA"?]

Furthermore, 12 of the HARs were located near genes involved in brain development. Topping off the list was HAR1, a section of DNA made up of 118 bases, or "letters." A computational analysis of HAR1 showed that is essentially the same in all mammals except humans. [It is a pity Gould is not here to see this, because it seems that Owen (as well was Lyell and Wallace) was right and Huxley (as well as Darwin and Gould) was wrong, in the "great hippocampus debate" in which "Owen had sought to establish our uniqueness by arguing that a small convolution of the human brain, the hippocampus minor, was absent in chimps and gorillas (and all other creatures), but present in Homo sapiens alone":

"... Thomas Henry Huxley invoked the same image in declining to pursue further the decisive victory he had won over Richard Owen in the great hippocampus debate: `Life is too short to occupy oneself with the slaying of the slain more than once.' Owen had sought to establish our uniqueness by arguing that a small convolution of the human brain, the hippocampus minor, was absent in chimps and gorillas (and all other creatures), but present in Homo sapiens alone. Huxley ... showed conclusively that all apes had a hippocampus, and that any discontinuity in the structure of primate brains lay between prosimians (lemurs and tarsiers) and all other primates (including humans), not between man and the great apes. Yet for a month, in April, 1861, all England watched as her two greatest anatomists waged war over a little bump on the brain. ... The Western world has yet to make its peace with Darwin and the implications of evolutionary theory. The hippocampus debate merely illustrates, in light relief, the greatest impediment to this reconciliation-our unwillingness to accept continuity between ourselves and nature, our ardent search for a criterion to assert our uniqueness. Again and again, the great naturalists have enunciated general theories of nature and made singular exceptions for humans. Charles Lyell ... envisioned a world in steady-state: no change through time in the complexity of life, with all organic designs present from the first. Yet man alone was created but a geological instant ago-a quantum jump in the moral sphere imposed upon the constancy of mere anatomical deign. And Alfred Russel Wallace, an ardent selectionist who far out-Darwined Darwin in his rigid insistence on natural selection as the sole directing force for evolutionary change made his only exception for the human brain ... Darwin himself, although he accepted strict continuity, was reluctant to expose his heresy. ... Chimps and gorillas have long been the battleground of our search for uniqueness; for if we could establish an unambiguous distinction-of kind rather than of degree-between ourselves and our closest relatives, we might gain the justification long sought for our cosmic arrogance. The battle shifted long ago from a simple debate about evolution: educated people now accept the evolutionary continuity between humans and apes. But we are so tied to our philosophical and religious heritage that we still seek a criterion for strict division between our abilities and those of chimpanzees. ... Many criteria have been tried, and one by one they have failed. The only honest alternative is to admit the strict continuity in kind between ourselves and chimpanzees. And what do we lose thereby? Only an antiquated concept of soul to gain a more humble, even exalting vision of our oneness with nature." (Gould, S.J., "A Matter of Degree," in "Ever Since Darwin: Reflections in Natural History," [1978], Penguin: London, 1991, reprint, pp.49-51)

To be sure, the discontinuity was not in the "hippocampus," but even better, in that part of the genome whch controls development of the cortex.

Indeed, as David Berlinski (after quoting part of the above) observed, even if Gould was right that there was "No distinction in kind rather than degree between ourselves and the chimps" that difference in degree was still vast, comparable to the "difference of degree" that "separates man from the Canadian Goose" in both "entering the air unaided and landing some distance from where they started"!:

"... Gould represents a charming intelligence corrupted by a shallow system of belief. No distinction in kind rather than degree between ourselves and the chimps? No distinction? Seriously, folks? Here is a simple operational test: The chimpanzees invariably are the ones behind the bars of their cages. There they sit, solemnly munching bananas, searching for lice, aimlessly loping around, baring their gums, waiting for the experiments to begin. No distinction? Chimpanzees cannot read or write; they do not paint, or compose music, or do mathematics; they form no real communities, only loose-knit wandering tribes; they do not dine and cannot cook; there is no record anywhere of their achievements; beyond the superficial, they show little curiosity; they are born, they live, they suffer and they die. No distinction? No species in the animal world organizes itself in the complex, dense, difficult fashion that is typical of human societies. There is no such thing as animal culture; animals do not compromise and cannot count; there is not a trace in the animal world of virtually any of the powerful and poorly understood powers and properties of the human mind; in all of history no animal has stood staring at the night sky in baffled and respectful amazement. The chimpanzees are static creatures solemnly poking for grubs with their sticks, inspecting one another for fleas. ... One may insist, of course, that all this represents difference merely of degree. Very well. Only a difference of degree separates man from the Canadian Goose. Individuals of both species are capable of entering the air unaided and landing some distance from where they started." (Berlinski, D., "Good as Gould," in "Black Mischief: Language, Life, Logic, Luck," Harcourt Brace Jovanovich: Boston MA, Second Edition, 1988, pp.293-295)

But in fact Gould's argument above is fallacious because the issue was not "continuity between humans and apes" in the sense of their sharing a common ancestor, because Owen, Wallace and Lyell accepted that (as I do). The issue was, as Gould himself said, "continuity" in the sense of "our uniqueness," i.e. was there something in the "brain" that "was absent in chimps and gorillas (and all other creatures), but present in Homo sapiens alone" (my emphasis)? And this new HAR1 gene evidence, of which further in this article (see part #3 when posted) it says, "the 18 base substitutions [are] unique to humans" and "It's a brand new structure, unique" (my emphasis), shows that Owen was right on that issue, while Huxley, Darwin and Gould were wrong.

In the time since humans and chimps split about 6 million years ago, HAR1 has racked up 18 base substitutions when only one or none would be expected by chance. [This is truly astonishing and as we have already seen in part #1, it cannot be explained by natural selection, which as Darwin pointed out, "is a slow process" that "can act only by short and slow steps" (Darwin, "The Origin of Species," 1872, pp.180,414). And so if "only one or none would be expected by chance" that only leaves design! But of course Darwinists reject that out of hand - which is their "cosmic arrogance" problem. ]

For comparison, the HAR1 region of chickens and chimps only differ by two substitutions, even though more than 310 million years have passed since they shared a common ancestor. [By "310 million years" is presumably meant twice the estimated ~150+5 million years that birds and chimps, and then chimps and humans, last "shared a common ancestor," which is the total genetic distance between the three lineages.

It is even more astomishing that a region of the vertebrate genome has been conserved for a total of "310 million years," across two classes (Aves and Mammalia) with only "two substitutions," yet in the ~5-8 million years since the chimp-human split, a total divergence time of ~10-16 million years, between to genuses (Pan and Homo) within the one family (Hominidae), there have been "18 base substitutions"!]

To be continued in part #3.

Stephen E. Jones, BSc (Biol).
`Evolution Quotes Book'