TY - JOUR
T1 - High lability of sexual system over 250 million years of evolution in morphologically conservative tadpole shrimps
AU - Mathers, Thomas C.
AU - Hammond, Robert L.
AU - Jenner, Ronald A.
AU - Zierold, Thorid
AU - Hänfling, Bernd
AU - Gómez, Africa
N1 - Funding Information:
This work was part of T.C.M.’s Ph.D. project ‘The genetics and evolutionary dynamics of reproductive mode in tadpole shrimps’ funded by a NERC CASE Studentship (NE/G012318/1). We are grateful to Diego Fontaneto, Marco Seminara, Dani Boix, Anna Badosa, Andy Green and Don Dasis for sending us samples. We would also like to thank Chris Venditti, Dave Lunt, Steve Moss and Elze Hesse for their help and advice. A.G. was funded by an Advanced NERC fellowship (NE/B501298/1).
PY - 2013/2/5
Y1 - 2013/2/5
N2 - Background: Sexual system is a key factor affecting the genetic diversity, population structure, genome structure and the evolutionary potential of species. The sexual system androdioecy - where males and hermaphrodites coexist in populations - is extremely rare, yet is found in three crustacean groups, barnacles, a genus of clam shrimps Eulimnadia, and in the order Notostraca, the tadpole shrimps. In the ancient crustacean order Notostraca, high morphological conservatism contrasts with a wide diversity of sexual systems, including androdioecy. An understanding of the evolution of sexual systems in this group has been hampered by poor phylogenetic resolution and confounded by the widespread occurrence of cryptic species. Here we use a multigene supermatrix for 30 taxa to produce a comprehensive phylogenetic reconstruction of Notostraca. Based on this phylogenetic reconstruction we use character mapping techniques to investigate the evolution of sexual systems. We also tested the hypothesis that reproductive assurance has driven the evolution of androdioecy in Notostraca. Results: Character mapping analysis showed that sexual system is an extremely flexible trait within Notostraca, with repeated shifts between gonochorism and androdioecy, the latter having evolved a minimum of five times. In agreement with the reproductive assurance hypothesis androdioecious notostracans are found at significantly higher latitudes than gonochoric ones indicating that post glacial re-colonisation may have selected for the higher colonisation ability conferred by androdioecy. Conclusions: In contrast to their conserved morphology, sexual system in Notostraca is highly labile and the rare reproductive mode androdioecy has evolved repeatedly within the order. Furthermore, we conclude that this lability of sexual system has been maintained for at least 250 million years and may have contributed to the long term evolutionary persistence of Notostraca. Our results further our understanding of the evolution of androdioecy and indicate that reproductive assurance is a recurrent theme involved in the evolution of this sexual system.
AB - Background: Sexual system is a key factor affecting the genetic diversity, population structure, genome structure and the evolutionary potential of species. The sexual system androdioecy - where males and hermaphrodites coexist in populations - is extremely rare, yet is found in three crustacean groups, barnacles, a genus of clam shrimps Eulimnadia, and in the order Notostraca, the tadpole shrimps. In the ancient crustacean order Notostraca, high morphological conservatism contrasts with a wide diversity of sexual systems, including androdioecy. An understanding of the evolution of sexual systems in this group has been hampered by poor phylogenetic resolution and confounded by the widespread occurrence of cryptic species. Here we use a multigene supermatrix for 30 taxa to produce a comprehensive phylogenetic reconstruction of Notostraca. Based on this phylogenetic reconstruction we use character mapping techniques to investigate the evolution of sexual systems. We also tested the hypothesis that reproductive assurance has driven the evolution of androdioecy in Notostraca. Results: Character mapping analysis showed that sexual system is an extremely flexible trait within Notostraca, with repeated shifts between gonochorism and androdioecy, the latter having evolved a minimum of five times. In agreement with the reproductive assurance hypothesis androdioecious notostracans are found at significantly higher latitudes than gonochoric ones indicating that post glacial re-colonisation may have selected for the higher colonisation ability conferred by androdioecy. Conclusions: In contrast to their conserved morphology, sexual system in Notostraca is highly labile and the rare reproductive mode androdioecy has evolved repeatedly within the order. Furthermore, we conclude that this lability of sexual system has been maintained for at least 250 million years and may have contributed to the long term evolutionary persistence of Notostraca. Our results further our understanding of the evolution of androdioecy and indicate that reproductive assurance is a recurrent theme involved in the evolution of this sexual system.
KW - Androdioecy
KW - Character evolution
KW - Notostraca
KW - Phylogeny
KW - Sexual system
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U2 - 10.1186/1471-2148-13-30
DO - 10.1186/1471-2148-13-30
M3 - Article
C2 - 23384124
AN - SCOPUS:84873275201
VL - 13
JO - BMC Evolutionary Biology
JF - BMC Evolutionary Biology
IS - 1
M1 - 30
ER -