scholarly journals Different behaviour of mitochondrial and nuclear markers: introgression and the evolutionary history of Chrysocarabus (Coleoptera: Carabidae)

2006 ◽  
Vol 17 (3) ◽  
Author(s):  
Andreas Düring ◽  
Martina Brückner ◽  
Dietrich Mossakowski

Phylogenetic analyses of Chrysocarabus taxa using different markers result in different phylogenetic trees. In particular, the mitochondrial gene tree contradicts the results of morphological and inbreeding studies. Two very different haplotypes of Carabus splendens Olivier, 1790 do not form a clade within this phylogenetic tree. We have earlier proposed that contradictory results are due to introgression. To verify our hypothesis, we analysed the internal transcribed spacer 2. No substitutions were observed in these nuclear sequences between the individuals of Carabus splendens, which contain the different mitochondrial haplotypes in question. The differences in the gene trees based on mitochondrial and nuclear sequences can be explained with at least two introgression events.

2020 ◽  
Author(s):  
Paul D. Blischak ◽  
Coleen E. Thompson ◽  
Emiko M. Waight ◽  
Laura S. Kubatko ◽  
Andrea D. Wolfe

AbstractReticulate evolutionary events are hallmarks of plant phylogeny, and are increasingly recognized as common occurrences in other branches of the Tree of Life. However, inferring the evolutionary history of admixed lineages presents a difficult challenge for systematists due to genealogical discordance caused by both incomplete lineage sorting (ILS) and hybridization. Methods that accommodate both of these processes are continuing to be developed, but they often do not scale well to larger numbers of species. An additional complicating factor for many plant species is the occurrence of whole genome duplication (WGD), which can have various outcomes on the genealogical history of haplotypes sampled from the genome. In this study, we sought to investigate patterns of hybridization and WGD in two subsections from the genus Penstemon (Plantaginaceae; subsect. Humiles and Proceri), a speciose group of angiosperms that has rapidly radiated across North America. Species in subsect. Humiles and Proceri occur primarily in the Pacific Northwest of the United States, occupying habitats such as mesic, subalpine meadows, as well as more well-drained substrates at varying elevations. Ploidy levels in the subsections range from diploid to hexaploid, and it is hypothesized that most of the polyploids are hybrids (i.e., allopolyploids). To estimate phylogeny in these groups, we first developed a method for estimating quartet concordance factors (QCFs) from multiple sequences sampled per lineage, allowing us to model all haplotypes from a polyploid. QCFs represent the proportion of gene trees that support a particular species quartet relationship, and are used for species network estimation in the program SNaQ (Solís-Lemus & Ané. 2016. PLoS Genet. 12:e1005896). Using phased haplotypes for nuclear amplicons, we inferred species trees and networks for 38 taxa from P. subsect. Humiles and Proceri. Our phylogenetic analyses recovered two clades comprising a mix of taxa from both subsections, indicating that the current taxonomy for these groups is inconsistent with our estimates of phylogeny. In addition, there was little support for hypotheses regarding the formation of putative allopolyploid lineages. Overall, we found evidence for the effects of both ILS and admixture on the evolutionary history of these species, but were able to evaluate our taxonomic hypotheses despite high levels of gene tree discordance. Our method for estimating QCFs from multiple haplotypes also allowed us to include species of varying ploidy levels in our analyses, which we anticipate will help to facilitate estimation of species networks in other plant groups as well.


2020 ◽  
Author(s):  
Yuji Matsuo ◽  
Akinao Nose ◽  
Hiroshi Kohsaka

AbstractSpeed and trajectory of locomotion are characteristic traits of individual species. During evolution, locomotion kinematics is likely to have been tuned for survival in the habitats of each species. Although kinematics of locomotion is thought to be influenced by habitats, the quantitative relation between the kinematics and environmental factors has not been fully revealed. Here, we performed comparative analyses of larval locomotion in 11 Drosophila species. We found that larval locomotion kinematics are divergent among the species. The diversity is not correlated to the body length but is correlated instead to the minimum habitat temperature of the species. Phylogenetic analyses using Bayesian inference suggest that the evolutionary rate of the kinematics is diverse among phylogenetic trees. The results of this study imply that the kinematics of larval locomotion has diverged in the evolutionary history of the genus Drosophila and evolved under the effects of the minimum ambient temperature of habitats.


Algorithms ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 225
Author(s):  
Broňa Brejová ◽  
Rastislav Královič

In the reconciliation problem, we are given two phylogenetic trees. A species tree represents the evolutionary history of a group of species, and a gene tree represents the history of a family of related genes within these species. A reconciliation maps nodes of the gene tree to the corresponding points of the species tree, and thus helps to interpret the gene family history. In this paper, we study the case when both trees are unrooted and their edge lengths are known exactly. The goal is to root them and to find a reconciliation that agrees with the edge lengths. We show a linear-time algorithm for finding the set of all possible root locations, which is a significant improvement compared to the previous O(N3logN) algorithm.


PLoS Genetics ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. e1009095
Author(s):  
Thomas C. Nelson ◽  
Angela M. Stathos ◽  
Daniel D. Vanderpool ◽  
Findley R. Finseth ◽  
Yao-wu Yuan ◽  
...  

Inferences about past processes of adaptation and speciation require a gene-scale and genome-wide understanding of the evolutionary history of diverging taxa. In this study, we use genome-wide capture of nuclear gene sequences, plus skimming of organellar sequences, to investigate the phylogenomics of monkeyflowers in Mimulus section Erythranthe (27 accessions from seven species). Taxa within Erythranthe, particularly the parapatric and putatively sister species M. lewisii (bee-pollinated) and M. cardinalis (hummingbird-pollinated), have been a model system for investigating the ecological genetics of speciation and adaptation for over five decades. Across >8000 nuclear loci, multiple methods resolve a predominant species tree in which M. cardinalis groups with other hummingbird-pollinated taxa (37% of gene trees), rather than being sister to M. lewisii (32% of gene trees). We independently corroborate a single evolution of hummingbird pollination syndrome in Erythranthe by demonstrating functional redundancy in genetic complementation tests of floral traits in hybrids; together, these analyses overturn a textbook case of pollination-syndrome convergence. Strong asymmetries in allele-sharing (Patterson’s D-statistic and related tests) indicate that gene-tree discordance reflects ancient and recent introgression rather than incomplete lineage sorting. Consistent with abundant introgression blurring the history of divergence, low-recombination and adaptation-associated regions support the new species tree, while high-recombination regions generate phylogenetic evidence for sister status for M. lewisii and M. cardinalis. Population-level sampling of core taxa also revealed two instances of chloroplast capture, with Sierran M. lewisii and Southern Californian M. parishii each carrying organelle genomes nested within respective sympatric M. cardinalis clades. A recent organellar transfer from M. cardinalis, an outcrosser where selfish cytonuclear dynamics are more likely, may account for the unexpected cytoplasmic male sterility effects of selfer M. parishii organelles in hybrids with M. lewisii. Overall, our phylogenomic results reveal extensive reticulation throughout the evolutionary history of a classic monkeyflower radiation, suggesting that natural selection (re-)assembles and maintains species-diagnostic traits and barriers in the face of gene flow. Our findings further underline the challenges, even in reproductively isolated species, in distinguishing re-use of adaptive alleles from true convergence and emphasize the value of a phylogenomic framework for reconstructing the evolutionary genetics of adaptation and speciation.


2017 ◽  
Author(s):  
Ryan M. Moore ◽  
Amelia O. Harrison ◽  
Sean M. McAllister ◽  
Shawn W. Polson ◽  
K. Eric Wommack

ABSTRACTPhylogenetic trees are an important analytical tool for evaluating community diversity and evolutionary history. In the case of microorganisms, the decreasing cost of sequencing has enabled researchers to generate ever-larger sequence datasets, which in turn have begun to fill gaps in the evolutionary history of microbial groups. However, phylogenetic analyses of these types of datasets create complex trees that can be challenging to interpret. Scientific inferences made by visual inspection of phylogenetic trees can be simplified and enhanced by customizing various parts of the tree. Yet, manual customization is time-consuming and error prone, and programs designed to assist in batch tree customization often require programming experience or complicated file formats for annotation. Iroki, a user-friendly web interface for tree visualization, addresses these issues by providing automatic customization of large trees based on metadata contained in tab-separated text files. Iroki’s utility for exploring biological and ecological trends in sequencing data was demonstrated through a variety of microbial ecology applications in which trees with hundreds to thousands of leaf nodes were customized according to extensive collections of metadata. The Iroki web application and documentation are available at https://www.iroki.net or through the VIROME portal (http://virome.dbi.udel.edu). Iroki’s source code is released under the MIT license and is available at https://github.com/mooreryan/iroki.


2019 ◽  
pp. 214-249
Author(s):  
Glenn-Peter Sætre ◽  
Mark Ravinet

How can genetics and genomics be used to understand the evolutionary history of organisms? This chapter focuses on such methods. First, the field of phylogenetics is introduced, as a way to visualize and quantify the evolutionary relationships among species. The chapter outlines how we go from aligning DNA sequence data to building gene trees and we argue that “tree-thinking” is fundamentally important for understanding evolution. The chapter also goes beyond phylogenetic trees to focus on phylogeography, i.e. the understanding of evolutionary relationships in a spatial context. More recently, the explosion of genomic data from ancient and modern human populations has made this an extremely exciting field which is transforming our understanding of our own evolutionary history. Before that, though, the chapter reviews how modern phylogenetics has arisen from historical efforts to classify life on Earth.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8584 ◽  
Author(s):  
Ryan M. Moore ◽  
Amelia O. Harrison ◽  
Sean M. McAllister ◽  
Shawn W. Polson ◽  
K. Eric Wommack

Phylogenetic trees are an important analytical tool for evaluating community diversity and evolutionary history. In the case of microorganisms, the decreasing cost of sequencing has enabled researchers to generate ever-larger sequence datasets, which in turn have begun to fill gaps in the evolutionary history of microbial groups. However, phylogenetic analyses of these types of datasets create complex trees that can be challenging to interpret. Scientific inferences made by visual inspection of phylogenetic trees can be simplified and enhanced by customizing various parts of the tree. Yet, manual customization is time-consuming and error prone, and programs designed to assist in batch tree customization often require programming experience or complicated file formats for annotation. Iroki, a user-friendly web interface for tree visualization, addresses these issues by providing automatic customization of large trees based on metadata contained in tab-separated text files. Iroki’s utility for exploring biological and ecological trends in sequencing data was demonstrated through a variety of microbial ecology applications in which trees with hundreds to thousands of leaf nodes were customized according to extensive collections of metadata. The Iroki web application and documentation are available at https://www.iroki.net or through the VIROME portal http://virome.dbi.udel.edu. Iroki’s source code is released under the MIT license and is available at https://github.com/mooreryan/iroki.


2004 ◽  
Vol 72 (9) ◽  
pp. 5253-5261 ◽  
Author(s):  
Kwan Soo Ko ◽  
Jong-Wan Kim ◽  
Jong-Man Kim ◽  
Wonyong Kim ◽  
Sang-in Chung ◽  
...  

ABSTRACT The population structure of the Bacillus cereus group (52 strains of B. anthracis, B. cereus, and B. thuringiensis) was investigated by sequencing seven gene fragments (rpoB, gyrB, pycA, mdh, mbl, mutS, and plcR). Most of the strains were classifiable into two large subgroups in six housekeeping gene trees but not in the plcR tree. In addition, several consistent clusters were identified, which were unrelated to species distinction. Moreover, interrelationships among these clusters were incongruent in each gene tree. The incongruence length difference test and split decomposition analyses also showed incongruences between genes, suggesting horizontal gene transfer. The plcR gene was observed to have characteristics that differed from those of the other genes in terms of phylogenetic topology and pattern of sequence diversity. Thus, we suggest that the evolutionary history of the PlcR regulon differs from those of the other chromosomal genes and that recombination of the plcR gene may be frequent. The homogeneity of B. anthracis, which is depicted as an independent lineage in phylogenetic trees, is suggested to be of recent origin or to be due to the narrow taxonomic definition of species.


2020 ◽  
Vol 15 (3) ◽  
pp. 187-201
Author(s):  
Semen Yu. BODROV ◽  
Vera K. VASILJEVA ◽  
Innokentiy M. OKHLOPKOV ◽  
Nikolai V. MAMAYEV ◽  
Evgeniy S. ZAKHAROV ◽  
...  

Author(s):  
Sergio A Muñoz-Gómez ◽  
Keira Durnin ◽  
Laura Eme ◽  
Christopher Paight ◽  
Christopher E Lane ◽  
...  

Abstract A most interesting exception within the parasitic Apicomplexa is Nephromyces, an extracellular, probably mutualistic, endosymbiont found living inside molgulid ascidian tunicates (i.e., sea squirts). Even though Nephromyces is now known to be an apicomplexan, many other questions about its nature remain unanswered. To gain further insights into the biology and evolutionary history of this unusual apicomplexan, we aimed to (1) find the precise phylogenetic position of Nephromyces within the Apicomplexa, (2) search for the apicoplast genome of Nephromyces, and (3) infer the major metabolic pathways in the apicoplast of Nephromyces. To do this, we sequenced a metagenome and a metatranscriptome from the molgulid renal sac, the specialized habitat where Nephromyces thrives. Our phylogenetic analyses of conserved nucleus-encoded genes robustly suggest that Nephromyces is a novel lineage sister to the Hematozoa, which comprises both the Haemosporidia (e.g., Plasmodium) and the Piroplasmida (e.g., Babesia and Theileria). Furthermore, a survey of the renal sac metagenome revealed 13 small contigs that closely resemble the genomes of the non-photosynthetic reduced plastids, or apicoplasts, of other apicomplexans. We show that these apicoplast genomes correspond to a diverse set of most closely related but genetically divergent Nephromyces lineages that co-inhabit a single tunicate host. In addition, the apicoplast of Nephromyces appears to have retained all biosynthetic pathways inferred to have been ancestral to parasitic apicomplexans. Our results shed light on the evolutionary history of the only probably mutualistic apicomplexan known, Nephromyces, and provide context for a better understanding of its life style and intricate symbiosis.


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