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SONG OF DARWIN. "The more I study nature, the more I become impressed […] that the contrivances and beautiful adaptations [acquired through natural selection] transcend in an incomparable degree [those] which the most fertile imagination of the most imaginative man could suggest with unlimited time at his disposal." https://lnkd.in/eykUy37 View in LinkedIn

FRAGMENT FROM NATURE follows on from the extensive subject about a range of parasites profoundly that affect host behavior and brain activity. We are also hosts to symbiotic gut bacteria, the gut microbiome, that also has profound effects on our brain, mood and development. These gut symbionts keep pathological bacteria under control. When the ecological balance is disturbed, the pathological bacteria gain a dominant position and cause illness. View in LinkedIn

THE QUESTION. "Why does an onion require five times more of it (the genome) than a human? " http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004351 View in LinkedIn

BROAD ONION TEST. "Importantly, the comparison is not restricted to onions versus humans. It could as easily be between pufferfish and lungfish, which differ by ∼350-fold, or members of the genus Allium, which have more than a 4-fold range in genome size that is not the result of polyploidy." http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004351 View in LinkedIn

THE ONION TEST. "The domestic onion, Allium cepa, is a diploid plant (2n = 16) with a haploid genome size of roughly 16 billion base pairs (16 Gbp), or about five times larger than humans." http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004351 View in LinkedIn

RELATIVE DIFFERENCES. "Even closely related species with very similar biological properties and the same ploidy level can differ significantly in genome size." http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004351 View in LinkedIn

LARGE GENOMES. "Organisms that have very large genomes are not few in number or outliers—for example, of the >200 salamander genomes analyzed thus far, all are between four and 35 times larger than the human genome." http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004351 View in LinkedIn

UNRELATED TO COMPLEXITY. "Genome size varies independently of intuitive notions of organism complexity or presumed number of protein-coding genes. For example, a human genome contains eight times more DNA than that of a pufferfish but is 40 times smaller than that of a lungfish." http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004351 View in LinkedIn

"GENOME SIZE varies enormously among species: at least 7,000-fold among animals and 350-fold even within vertebrates." http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004351 View in LinkedIn

JUNK DNA APOLOGIST AND CONTRARIANS (Alexander Palazzo, and T. Ryan Gregory, among others) make the case that most non-coding DNA has (so far) not had a function assigned to it. They raise excellent points about how little we know about their functioning. Since the majority of the genome is non-coding DNA, genome size differences are of considerable relevance. Deep dive to follow. https://lnkd.in/eT5V5Xc View in LinkedIn