Dating the time of origin of major clades gay black and white dating

Posted by / 07-Dec-2019 21:04

The genus Pinus has traditionally been divided into two major clades based on the number of vascular leaf bundles (either one or two bundles, corresponding to subgenera Strobus and Pinus) [1], and previous studies had not been able to consistently resolve relationships within these major clades. [5] proposed a new classification based on phylogenetic trees inferred from two chloroplast genes, dividing the pines into two subgenera (Pinus and Strobus), four sections (sections Pinus and Trifoliae in subgenus Pinus and sections Parrya and Quinquefoliae in subgenus Strobus) and 11 subsections (Australes, Ponderosae, Contortae, Pinus, Pinaster, Strobus, Krempfianae, Cembroides, Balfourianae and Nelsoniae).Although taxonomically comprehensive and widely accepted, their study relied exclusively on sequences from the mat K and rbc L genes, and was thus unable to resolve relationships within several of the subsections. [6] analyzed the entire chloroplast genome for 107 pine species, which largely confirmed the structure proposed by Gernandt et al.The taxonomy of pines (genus Pinus) is widely accepted and a robust gene tree based on entire plastome sequences exists.However, there is a large discrepancy in estimated divergence times of major pine clades among existing studies, mainly due to differences in fossil placement and dating methods used.Subsequent studies have improved phylogenetic resolution, but have mostly focused on specific subclades (e.g. [5] and provided better resolution for much of the tree.However, despite the detailed chloroplast data and the availability of potential fossil calibration points, comprehensive time-calibrated molecular phylogenetic trees remain lacking.

The probabilistic calibration prior accounts for uncertainties underlying the age of the fossil and the likelihood that the true divergence occurred before its first appearance in the fossil record [19, 37].

No conclusion has been reached to date as to whether estimated divergence times are in agreement between the two methods [44–46].

Here, we build the first comprehensive phylogenetic tree of Pinus calibrated with a large number of fossils across all major clades, using both the ND and the FBD method.

We currently lack a dated molecular phylogeny that makes use of the rich pine fossil record, and this study is the first to estimate the divergence dates of pines based on a large number of fossils (21) evenly distributed across all major clades, in combination with applying both node and tip dating methods.

We present a range of molecular phylogenetic trees of Pinus generated within a Bayesian framework.

dating the time of origin of major clades-47dating the time of origin of major clades-72dating the time of origin of major clades-87

This method acknowledges that extant species and fossils are both part of the same evolutionary process [41].

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