Posts Tagged ‘genetics’

In The Origin of Species, Charles Darwin developed his revolutionary theory of “slight, successive” evolutionary changes. During the mid-nineteenth century, however, knowledge about genes and genetics was speculative at best, no less the evolution of genes.

In fact, Darwin abandoned the scientific method and declared that his theory of evolution was based on speculation –

I am quite conscious that my speculations run quite beyond the bounds of true science.

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In The Origin of Species, Charles Darwin proposed that evolution proceeds by “slight, successive changes”. Although molecular biology was largely unknown by Darwin during the nineteenth century, “slight, successive” molecular changes have become a cornerstone in the study of biological evolution.

Since steroid hormones are known to perform sophisticated regulatory functions in microbes to man, the path of steroid evolution has entered center stage in the realm of investigative molecular biology.

Steroids hormones were first discovered in the mid-twentieth century by American chemist Edward Calvin Kendall while working at the Mayo Clinic. In 1950, Kendall and colleague Philip Hench, along with Swiss chemist Tadeus Reichstein were awarded the Nobel Prize in Physiology or Medicine for “their discoveries relating to the hormones of the adrenal cortex, their structure and biological effects.” Continue Reading

Charles Darwin never mentions the 1856 fossil discovery in the Neander Valley limestone quarry located in Germany in The Origin of Species in 1859 nor in any of the six subsequent editions. Even in The Descent of Man, Darwin did not endorse the Neanderthals as a potential ancestral transitional link to humans.

In fact, the discovery was a problem since the Neanderthal skulls are larger than human skulls. Darwin had argued that the advancement of evolution proceeded through “slight, successive changes”.

The Neanderthal fossils created a dilemma for Darwin, how could a larger brain precede a smaller brain? Darwin cautiously noted, that “it must be admitted that some skulls of very high antiquity, such as the famous one of Neanderthal, are well developed and capacious [large]”. For Darwin, the Neanderthal skulls were too large to have preceded humans. Continue Reading

On the 2012 presidential campaign tour in New Hampshire, the current Republican front-runner, Texas Governor Rick Perry, set off a media firestorm  responding to a question from a boy as prompted by his mother about the age of the Earth and evolution.

“I hear your mom was asking about evolution,” Perry said. “That’s a theory that is out there — and it’s got some gaps in it.” Continue Reading

The puzzling platypus was discovered long before Charles Darwin published The Origin of Species. This duck-billed oddity is like a mammal, a bird, and a reptile all in one species.

When the platypus, nicknamed the “watermole,” was first discovered in 1797 by early European settlers near the Hawkesbury River, outside Sydney, it triggered a lasting controversy. The perplexed local governor, Captain John Hunter, sent specimens back to Mother England for study.

The “watermole” was equally mystifying in England. Zoologists George Shaw suggested it was a “freak imposture” sold to gullible seamen by Chinese taxidermists. Suspecting fraud, they tried to pry the “duck’s bill” off of the pelt, leaving marks on the bill that are still visible today at the British Museum in London.
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Francis Collins, the past director of the Human Genome Project and current director of the National Institute of Health (NIH), and Charles Darwin have pursued a common cause—a belief in evolution supported by deductive reasoning.

Both Collins and Darwin abandoned the inductive Scientific Method reasoning process to embrace deductive reasoning. Their resulting conclusions on “Junk DNA” and “Natural Selection” are similar.

While the DNA regions not known to code for proteins were thought to be only “Junk DNA” by Collins, Darwin thought that Natural Section was the driving force of evolution. Continue Reading

Charles Darwin in The Origin of Species explains the role of natural selection in evolution: “I do believe that natural selection will generally act very slowly, only over long periods of time…. natural selection acts slowly by accumulating slight, successive, favorable variations.” The key to evolution is the accumulation of “slight, successive” changes.

In 1995, Edward B. Lewis, Christiane Nüsslein-Volhard, and Eric F. Wieschaus were awarded the Nobel Prize in Physiology or Medicine for their work on HOX genes. During the 1950’s, geneticist Edward B Lewis discovered the Bithorax complex (BX-C) group of HOX genes in the fruit fly Drosophila melanogaster. Continue Reading

In The Origin of Species, Charles Darwin envisioned that “natural selection acts solely by accumulating slight, successive, favourable variations; it can produce no great or sudden modifications.”

Since 1859, the search for Darwin’s “slight, successive” accumulated actions of natural selection has become a driving scientific and societal phenomenon. In 1872, the British Parliament commissioned the HMS Challenger for first international exploration to discover the “missing links” resulting from natural selection.

Like the HMS Challenger experience, evidence for “slight, successive” evolutionary changes continues to be an elusive pursuit—in the fossil record and now in molecular biology. Darwin’s dilemma deepens with the latest evidence from the Denisova caves in Russia.

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Critical of The Origin of Species, Charles Darwin in a letter to Hugh Falconer in October 1862, Darwin wrote, “I look at it as absolutely certain that very much in the Origin will be proved to be rubbish; but I expect and hope that the framework will stand.” 

Darwin’s conceptual framework of “slight, successive” changes over time had remained intact for 150 years, until the evidence from the human genome project delivered the decisive destruction of the original “framework”.   

J. Craig Venter, the microbiologist turned entrepreneur that mapped the human genome and re-produced what he calls “the first synthetic species”, concluded during a 60-Minute CBS interview with Steve Kroft on Sunday, November 21 that the human genome project has been a “bust”. Continue Reading

In his autobiography, Charles Darwin notes, “Towards the end of the work I gave my well abused hypothesis of Pangenesis. An unverified hypothesis is of little or no value”—the First-Wave of evolutionary thought. Today, Darwin’s sentiments on pangenesis have re-emerged, however, this time on genetics.

In this week’s edition of the journal Science published by the American Association for the Advancement of Science (AAAS), the focus is on epigenetics. An on-line issue even features a video by Science editor Guy Riddihough asking a number of top researchers a simple question: “What’s your definition of epigenetics?” And, “Their answers aren’t quite so simple,” according to Riddihough. Continue Reading