Jumping genes; an essay shows importance (Introduction)

by David Turell , Saturday, March 19, 2016, 18:37 (3171 days ago) @ David Turell

They are all over the place at all levels of complexity in organisms from single cells upwards:-https://aeon.co/essays/genes-that-jump-species-does-this-shake-the-tree-of-life?utm_source=Aeon+Newsletter&utm_campaign=224349e1e1-Saturday_newsletter_19_March_20163_18_2016&utm_medium=email&utm_term=0_411a82e59d-224349e1e1-68942561-"What has become increasingly clear in the past 10 years is that this liberal genetic exchange is definitely not limited to the DNA of the microscopic world. It likewise happens to genes that belong to animals, fungi and plants, collectively known as eukaryotes because they boast nuclei in their cells. The ancient communion between ferns and hornworts is the latest in a series of newly discovered examples of horizontal gene transfer: when DNA passes from one organism to another generally unrelated one, rather than moving ‘vertically' from parent to child. In fact, horizontal gene transfer has happened between all kinds of living things throughout the history of life on the planet - not just between species, but also between different kingdoms of life. Bacterial genes end up in plants; fungal genes wind up in animals; snake and frog genes find their way into cows and bats. It seems that the genome of just about every modern species is something of a mosaic constructed with genes borrowed from many different forms of life.-"What scientists have seen is just a little tip of an immense iceberg,' says Antonio Teixeira, a biologist at the University of Brasilia. W Ford Doolittle, a biochemist at Dalhousie University in Nova Scotia, agrees: horizontal gene transfer, he wrote recently ‘is far more pervasive and more radical in its consequences than we could have guessed just a decade ago'. Researchers have now discovered so many examples of gene transfer between species and kingdoms of life - with many more surely to come - that they have to adjust their understanding of how evolution works. -***-"At this point, the tally is too high to ignore. Scientists can no longer write off gene-swapping among eukaryotes - and between prokaryotes and eukaryotes - as inconsequential. Clearly genes have all kinds of ways of journeying between the kingdoms of life: sometimes in large and sudden leaps; other times in incremental steps over millennia. -***-"The fact that horizontal gene transfer happens among eukaryotes does not require a complete overhaul of standard evolutionary theory, but it does compel us to make some important adjustments. According to textbook theories of evolution, the major route of genes moving between organisms is parent to child - whether through sex or asexual cloning - not this sneaky business of escorting genes between unrelated organisms. We must now acknowledge that, even among the most complex organisms, vertical is not the only direction in which genes travel.-***-"In some cases, this genetic hopscotching ‘could exert a very powerful evolutionary force', says Li. ‘It can introduce novelties that cannot be achieved by gradual genetic mutations.' -***-"As far as DNA is concerned, however, the supposed walls between species are not nearly so impermeable. Up in the branches of the great tree of life, we are no longer immersed in the ancient communal pool that watered its tangled roots. Yet we cannot escape the winds of promiscuity. Even today - as was true from the start - ‘our' genes are not ours alone.-Comment: This is one guidance mechanism by which God could have directed evolution. The perfect dabble! I've skipped the examples of the studies. Fascinating.