tag:blogger.com,1999:blog-8386055846297828307.post7469665662372698157..comments2024-03-28T07:34:49.133+01:00Comments on The Genealogical World of Phylogenetic Networks: Why do we still use trees for the Neandertal genealogy?Unknownnoreply@blogger.comBlogger4125tag:blogger.com,1999:blog-8386055846297828307.post-71450188753712900582014-09-30T16:26:17.042+02:002014-09-30T16:26:17.042+02:00Yes, I think that species boundaries are rather fu...Yes, I think that species boundaries are rather fuzzy things when dealing with the population level. Whether any one population or individual is "in" one species or the other can be arbitrary. That is the advantage of using network diagrams, that it can make this point of view clear. At the population level the "Recent Africa" idea is probably the same as the "Multiregional" one, and we need to get a better analytical grasp on how best to relate population genetics to phylogenetics. Networks will help in this regard. / DavidDavid Morrisonhttps://www.blogger.com/profile/05469392205239443608noreply@blogger.comtag:blogger.com,1999:blog-8386055846297828307.post-76803814909727730702014-09-26T23:19:17.052+02:002014-09-26T23:19:17.052+02:00Thanks for the reply. I used "hybridization&q...Thanks for the reply. I used "hybridization" more or less as synonymous with introgression, since my focus was to contrast with ancient structure, even though at a level where such structure would perhaps be itself classified as admixture or hybridization, even though the lines get blurry; sort of like the blurriness of ring-species but for cladogenesis and chronospeciation (or just "gradual divergence" to be totally agnostic regarding species barriers) happening at the same time.<br /><br />The picture I had in mind was actually more like the mtDNA network on this page, it already gives the "impression" that sapiens are not homogeneously far from neanderthals (but regarding mtDNA in particular, if I'm not mistaken, they're a tiny bit closer to modern Africans, but only to a degree that was considered meaningless), because there is no single "sapiens line" but this network of lines, and one "side" has more connections with the neanderthal line/network, whereas the other has had a bit more of separation. <br /><br />Sometimes I think that if scientists had all the possible relevant data magically given by God or god-like aliens, even after years of analysis, it would be such a thing that would still be debatable whether it's better labeled as "multiregional" or "recent African origins", depending on the focus one have and the strictness of definitions.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8386055846297828307.post-70503042017939723302014-09-26T10:58:07.358+02:002014-09-26T10:58:07.358+02:00Thanks for your comment.
(1) It is often difficul...Thanks for your comment.<br /><br />(1) It is often difficult to distinguish between hybridization and introgression (aka admixture), since at the population level the former is simply the latter occurring over a short period of time. However, it seems likely that the more complex a splits graph is then the more likely it is that introgression has occurred rather than hybridization.<br /><br />(2) A webby-tree is still a network, not a tree. However, what you are describing is something like the admixture graphs that are currently used to analyze human evolution (see the post http://phylonetworks.blogspot.com/2012/09/admixture-graphs-evolutionary-networks.html) but with more reticulations. In the microbiology world one often sees networks with a tree-like main structure and a web of fainter lines representing reticulations.<br /><br />DavidDavid Morrisonhttps://www.blogger.com/profile/05469392205239443608noreply@blogger.comtag:blogger.com,1999:blog-8386055846297828307.post-14113676271789159702014-09-26T09:59:30.883+02:002014-09-26T09:59:30.883+02:00Does this sort of analysis bear any significance o...Does this sort of analysis bear any significance on models such as simple recent hybridization of pure lines versus a gradation of messier scenarios of structured populations and more gradations of admixture? Coincidentally I was just thinking that perhaps a tree-graph that was an "hybrid" of the single-line tree for Recent African Origins (plus hybridization lines/arrows), and the trellis line for classic multiregional model could provide a visualization of a webby-tree where the human "line" never interbred with Neandethals (or Denisovans) at the peak of divergence, but rather just had different degrees of contact/proximity at the beginning of the split, with smaller intermediate lines, like heidelbergensis, rhodesiensis, and sapiens idaltu, perhaps.<br /><br />Anonymousnoreply@blogger.com