[MARMAM] new publication on spinner dolphin population genetics

kim andrews kimandrews at gmail.com
Wed Apr 10 15:26:48 PDT 2013

Dear colleagues,

We are pleased to announce the publication of the following paper:

Andrews KR, Perrin WF, Oremus M, Karczmarski L, Bowen BW, Puritz JB, Toonen
RJ (2013) The evolving male: spinner dolphin (*Stenella longirostris*)
ecotypes are divergent at Y chromosome but not mtDNA or autosomal
markers. *Molecular
Ecology* DOI: 10.1111/mec.12193


The susceptibility of the Y chromosome to sexual selection may make this
chromosome an important player in the formation of reproductive isolating
barriers, and ultimately speciation. Here, we investigate the role of the Y
chromosome in phenotypic divergence and reproductive isolation of spinner
dolphin (*Stenella longirostris*) ecotypes. This species contains six known
ecotypes (grouped into four subspecies) that exhibit striking differences
in morphology, habitat and mating system, despite having adjacent or
overlapping ranges and little genetic divergence at previously studied
mtDNA and autosomal markers. We examined the phylogeographic structure for
all six ecotypes across the species range (*n *=* *261, 17 geographic
locations) using DNA sequences from three Y chromosome markers, two
maternally inherited mitochondrial (mtDNA) markers, and a biparentally
inherited autosomal intron. mtDNA and autosomal analyses revealed low
divergence (most ΦST values <0.1) between ecotypes and geographic regions,
concordant with previous studies. In contrast, Y intron analyses revealed
fixed differences amongst the three most phenotypically divergent groups: *
S. l. longirostris* vs. *S. l. roseiventris* vs. combined *S. l. orientalis*
/*S. l. centroamericana*/Tres Marias ecotypes). Another ecotype
(whitebelly), previously postulated to be a hybrid between the two
phenotypically most divergent ecotypes, had Y haplotypes from both putative
parent ecotypes, supporting a hybrid designation. Reduced introgression of
the Y chromosome has previously been observed in other organisms ranging
from insects to terrestrial mammals, and here we demonstrate this
phenomenon in a marine mammal with high dispersal capabilities. These
results indicate that reduced introgression of the Y chromosome occurs in a
wide taxonomic range of organisms and support the growing body of evidence
that rapid evolution of the Y chromosome is important in evolutionary


Kim Andrews, PhD
Postdoctoral Research Fellow
School of Biological Sciences
Durham University
South Road, Durham
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