TY  - JOUR
A1  - Tiedemann, Ralph
A1  - Paulus, Kirsten B.
A1  - Scheer, M.
A1  - Von Kistowski, K. G.
A1  - Skirnisson, K.
A1  - Bloch, D.
A1  - Dam, M.
T1  - Mitochondrial DNA and microsatellite variation in the eider duck (Somateria mollissima) indicate stepwise postglacial colonization of Europe and limited current long-distance dispersal
N2  - To unravel the postglacial colonization history and the current intercolony dispersal in the common eider, Somateria mollissima, we analysed genetic variation at a part of the mitochondrial control region and five unlinked autosomal microsatellite loci in 175 eiders from 11 breeding colonies, covering the entire European distribution range of this species. As a result of extreme female philopatry, mitochondrial DNA differentiation is substantial both among local colonies and among distant geographical regions. Our study further corroborates the previous hypothesis of a single Pleistocene refugium for European eiders. A nested clade analysis on mitochondrial haplotypes suggests that (i) the Baltic Sea eider population is genetically closest to a presumably ancestral population and that (ii) the postglacial recolonization progressed in a stepwise fashion via the North Sea region and the Faroe Islands to Iceland. Current long-distance dispersal is limited. Differentiation among colonies is much less pronounced at microsatellite loci. The geographical pattern of this nuclear genetic variation is to a large extent explained by isolation by distance. As female dispersal is very limited, the geographical pattern of nuclear variation is probably explained by male-mediated gene flow among breeding colonies. Our study provides genetic evidence for the assumed prominent postglacial colonization route shaping the present terrestrial fauna of the North Atlantic islands Iceland and the Faroes. It suggests that this colonization had been a stepwise process originating in continental Europe. It is the first molecular study on eider duck populations covering their entire European distribution range
Y1  - 2004
SN  - 0962-1083
ER  - 
TY  - JOUR
A1  - Ravaoarimanana, I. B.
A1  - Tiedemann, Ralph
A1  - Montagnon, D.
A1  - Rumpler, Y.
T1  - Molecular and cytogenetic evidence for cryptic speciation within a rare endemic Malagasy lemur, the Northern Sportive Lemur (Lepilemur septentrionalis)
N2  - Evolutionary relationships of different populations of the threatened malagasy lemur Lepilemur septentrimialis were assessed by sequence analysis of mitochondrial DNA (D-loop region and partial Cyt b gene). One hundred and fifty nine samples were collected from five main different localities in the northern part of Madagascar. We applied the phylogenetic species concept based on fixed diagnostic differences to determine the status of different geographical populations. No nucleotide site diagnoses Ankarana from Andrafiamena or Analamera. However, numerous fixed differences separate Sahafary from all other populations. These results were corroborated by phylogenetic trees. As previous cytogenetic studies, our molecular data suggest that two cryptic species of Lepilemur occur in the extreme north of Madagascar. This speciation is probably caused by chromosomal rearrangements in at least one of the evolutionary lineages. Our study comprises another striking example of how molecular genetic assay can detect phylogenetic discontinuities that are not reflected in traditional morphologically based taxonomies. Our study indicates that the Sahafary population is a hitherto undescribed endangered endemic species which urgently needs conservation efforts. (C) 2003 Elsevier Inc. All rights reserved
Y1  - 2004
SN  - 1055-7903
ER  - 
TY  - JOUR
A1  - Milinkovitch, M. C.
A1  - Monteyne, D.
A1  - Gibbs, J. P.
A1  - Fritts, T. H.
A1  - Tapia, W.
A1  - Snell, H. L.
A1  - Tiedemann, Ralph
A1  - Caccone, Adalgisa
A1  - Powell, J. R.
T1  - Genetic analysis of a successful repatriation programme : giant Galapagos tortoises
N2  - As natural populations of endangered species dwindle to precarious levels, remaining members are sometimes brought into captivity, allowed to breed and their offspring returned to the natural habitat. One goal of such repatriation programmes is to retain as much of the genetic variation of the species as possible. A taxon of giant GalApagos tortoises on the island of Espahola has been the subject of a captive breeding-repatriation programme for 33 years. Core breeders, consisting of 12 females and three males, have produced more than 1200 offspring that have been released on Espanola where in situ reproduction has recently been observed. Using microsatellite DNA markers, we have determined the maternity and paternity of 132 repatriated offspring. Contributions of the breeders are highly skewed. This has led to a further loss of genetic variation that is detrimental to the long-term survival of the population. Modifications to the breeding programme could alleviate this problem
Y1  - 2004
SN  - 0962-8452
ER  -