Journal Club 25 Sept 2016: Potential merger of ancient lineages in a passerine bird discovered based on evidence from host-specific ectoparasites
The occurrence of deep mtDNA lineages in an otherwise homogenous genome may suggest that populations have been isolated in allopatry for long periods of time, but have more recenly been mixed. Such merger of formerly isolated lineages is hypothesized to occur only under certain conditions. There are not many examples of this phenomenon, but a recent study by Block et al. (2015) is an exception. They show with mtDNA sequencing and microsatellite screening of a Malagasy passerine, Xanthomixis zosterops, may possibly represent a instance of merging of deep lineages. There is also very interesting data of host-specific feather lice in the genus Myrsidea, suggesting three major phylogroups. supporting allopatry in X. zosterops.
The sampling sites, mtDNA lineages of the two main players in the present study: X. zosterops and its associated Myrsidea (Figure 2 in Block et al.).
A new paper spreads some light on the conservation genetics of the giraffe. Traditionally, one giraffe species with up to eleven subspecies have been recognized. A new study by Fennessy et al. (2016), use data from mtDNA and 7 nuclear loci to conclude that at least four of these lineages should be considered as species under the genetic isolation criterion. The branches are quite deep and monophyletic and the finding thus seems robust. The upgrading of several subspecies to species status should have significant conservation implications.
Evolutionary relationships among Giraffe as determined by a coalescent multi-locus tree from seven nuclear loci (4,294 bp) from 105 giraffe individuals rooted with okapi. Identified are four monophyletic clades with significant support, p > 0.95: southern giraffe (G. giraffa, G. angolensis), Masai giraffe (G. tippelskirchi), reticulated giraffe (G. reticulata), and northern giraffe (G. antiquorum, G. camelopardalis, G. peralta, G. rothschildi). Figure 2A from Fenessey et al.
Attended ICE 2016 in Orlando, Florida, between 25-30 September. This congress ,with the Theme “Entomology without Borders”, attracted no less than c. 6,700 attendees. Several good symposia and great talks, for me peaking with the symposium about insect sex determination with Leo Beukeboom (University of Groningen) as main speaker, and some really good talks e.g. by Richard Meisel (University of Houston) about sex chromosomes and sex determination in muscid flies. We had a symposium called "Next-Generation Ecology, Morphology, and Genomics: What Can We Learn about the Evolution of Odonata?" where I gave a talk about sexual differential gene expression in Ischnura elegans (as can be seen by the serious certificate below). Both Maren Wellenreuther and Rachael Dudaniec gave great talks, about non-adaptive radiation in damselflies and genomic adaptation along an environmental gradient in range-expanding damselflies, respectively.