Stephen E. Jones

Creation/Evolution Quotes: Classified quotes: Molecular

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The following are previously unclassified quotes about Molecular, now classified under that heading, now classified under that heading, and under subheadings alphabetically by author and date, as a temporary intermediate step towards integrating them into my quotes pages proper.

Molecular

1. Phylogeny
• "... it means that what Darwin had in mind, and what biologists have been doing for more than a century, was misguided at best and at worst a waste of time"

"What Darwin could not have predicted was that a century after the publication of his On the Origin of Species, biologists would begin to use molecules such as proteins and DNA to uncover the shape of the tree of life. This approach has taken the biological stage by storm, and has produced many surprising results. Consider some of the announcements made during 1997 alone. The elephant shrew, consigned by traditional analysis to the order insectivores (which includes moles and hedgehogs), is in fact more closely related to its behemoth namesake, the true elephant. Cows are more closely related to dolphins than they are to horses. The duckbilled platypus, an egg-laying mammal from Australia, does not represent the most primitive form of mammal after all, but is on an equal evolutionary footing with those marsupial mammals from Australia, kangaroos and koalas. And forget examining the shape of seedlings in flowering plants to seek out their evolutionary history: molecular evidence shows that the microscopic form of pollen grains gives the best clues. But who cares about the true relatives of elephant shrews? Let cows take a dive in the ocean, if that's where their roots are. And platypuses are just cute, no matter who their closest cousin is. Flowers, well, their place is in a vase, isn't it, not at the centre of a debate over the tree of life. Maybe. But, if these results and countless others like them are correct, it means that what Darwin had in mind, and what biologists have been doing for more than a century, was misguided at best and at worst a waste of time." (Lewin, Roger [biochemist, former editor of New Scientist and science writer], "Family feuds," New Scientist, Vol. 157, No. 2118, 24 January 1998, pp.36-40, p.36)

• "convergent evolution is common. ... some segments of a gene are highly susceptible to mutation, so the chances of identical mutations in two separate species is much higher"

"The overall effect is that molecular phylogenetics is by no means as straightforward as its pioneers believed. For a start, convergent evolution is common. In 1995, Michael Donoghue and Michael Sanderson of Harvard University combed through data from 42 studies of morphological phylogenetics and 18 studies of molecular phylogenetics. They found that the levels of convergent evolution were similar. One reason is because some segments of a gene are highly susceptible to mutation, so the chances of identical mutations in two separate species is much higher than if mutations were equally distributed over the whole gene. The Byzantine dynamics of genome change has many other consequences for molecular phylogenetics, including the fact that different genes tell different stories." (Lewin, Roger [biochemist, former editor of New Scientist and science writer], "Family feuds," New Scientist, Vol. 157, No. 2118, 24 January 1998, pp.36-40, p.39)

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