Limits...
Does the genetic structure of spring snail Bythinella (Caenogastropoda, Truncatelloidea) in Bulgaria reflect geological history?

Osikowski A, Georgiev D, Hofman S, Falniowski A - Zookeys (2015)

Bottom Line: The genetic differentiation between the clades was found to be in the range p=2.4-11.8%.Much more distinct were clade V, found at one locality in NW Bulgaria, and clade IV, found at one locality in SE Bulgaria, close to the sea.Four populations were found in caves, but only one of these represented a distinct clade.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Comparative Anatomy, Institute of Zoology, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland.

ABSTRACT
Bythinella is a minute dioecious caenogastropod that inhabits springs in central and southern Europe. In the Balkans, previous studies have addressed its morphological and genetic differentiation within Greece and Romania while the Bulgarian species have remained poorly known. The aim of the present paper has been to expand the knowledge on the subject in Bulgaria. Shell morphology and anatomy of the reproductive organs were examined, and a fragment of the mitochondrial cytochrome oxidase subunit I (COI) gene and the nuclear ribosomal Internal Transcribed Spacer 1 (ITS-1) were sequenced from 15 populations. Additional sequences from eight previously studied populations were included in our analyses. Phylogenetic analyses revealed five main mitochondrial DNA clades, which were partly confirmed by analyses of the ITS-1 sequences. The genetic differentiation between the clades was found to be in the range p=2.4-11.8%. Most of the populations belonged to clade I, representing Bythinella hansboetersi, and were distributed in SW Bulgaria. Clades II and III inhabit areas adjacent to clade I and were most closely related with the latter clade. Much more distinct were clade V, found at one locality in NW Bulgaria, and clade IV, found at one locality in SE Bulgaria, close to the sea. Four populations were found in caves, but only one of these represented a distinct clade. Considering the observed pattern of interpopulation differentiation of Bythinella in Bulgaria, we can suppose that isolation between clades I, II and III may have been caused by glaciations during the Pleistocene. The time of isolation between the above three clades and clade IV coincides with the Messinian Salinity Crisis, and the time of isolation between the clade V and the other four most probably reflects the isolation of the Rhodopes from western Balkan Mts by the seawater of the Dacic Basin.

No MeSH data available.


Geographical distribution of COI clades. Compare with Figure 3.
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4591597&req=5

Figure 4: Geographical distribution of COI clades. Compare with Figure 3.

Mentions: In the COI trees five main clades could be distinguished for the Bulgarian populations (Figs 3–4). Clade I included the largest number of haplotypes covering an area from the Rhodopes Mts through the Maritsa Valley to the Stara Planina and Sredna Gora Mts. This clade is characterized by a low sequence divergence (p-distance within this group = 0.008, Table 2). The relationships between the haplotypes of this clade are depicted in a haplotype network in Fig. 5. Most haplotypes from this clade belonged to snails inhabiting surface waters while two of them represent cave populations (Fig. 3). This clade represents several nominal species: Bythinellaangelovi, Bythinelladierkingi, Bythinellagloeeri, Bythinellahansboetersi, Bythinellaravnogorica, Bythinellarhodopensis, Bythinellarilaensis, Bythinellaslaveyae, and Bythinellasrednogorica, in fact based mostly on their locations.


Does the genetic structure of spring snail Bythinella (Caenogastropoda, Truncatelloidea) in Bulgaria reflect geological history?

Osikowski A, Georgiev D, Hofman S, Falniowski A - Zookeys (2015)

Geographical distribution of COI clades. Compare with Figure 3.
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591597&req=5

Figure 4: Geographical distribution of COI clades. Compare with Figure 3.
Mentions: In the COI trees five main clades could be distinguished for the Bulgarian populations (Figs 3–4). Clade I included the largest number of haplotypes covering an area from the Rhodopes Mts through the Maritsa Valley to the Stara Planina and Sredna Gora Mts. This clade is characterized by a low sequence divergence (p-distance within this group = 0.008, Table 2). The relationships between the haplotypes of this clade are depicted in a haplotype network in Fig. 5. Most haplotypes from this clade belonged to snails inhabiting surface waters while two of them represent cave populations (Fig. 3). This clade represents several nominal species: Bythinellaangelovi, Bythinelladierkingi, Bythinellagloeeri, Bythinellahansboetersi, Bythinellaravnogorica, Bythinellarhodopensis, Bythinellarilaensis, Bythinellaslaveyae, and Bythinellasrednogorica, in fact based mostly on their locations.

Bottom Line: The genetic differentiation between the clades was found to be in the range p=2.4-11.8%.Much more distinct were clade V, found at one locality in NW Bulgaria, and clade IV, found at one locality in SE Bulgaria, close to the sea.Four populations were found in caves, but only one of these represented a distinct clade.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Comparative Anatomy, Institute of Zoology, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland.

ABSTRACT
Bythinella is a minute dioecious caenogastropod that inhabits springs in central and southern Europe. In the Balkans, previous studies have addressed its morphological and genetic differentiation within Greece and Romania while the Bulgarian species have remained poorly known. The aim of the present paper has been to expand the knowledge on the subject in Bulgaria. Shell morphology and anatomy of the reproductive organs were examined, and a fragment of the mitochondrial cytochrome oxidase subunit I (COI) gene and the nuclear ribosomal Internal Transcribed Spacer 1 (ITS-1) were sequenced from 15 populations. Additional sequences from eight previously studied populations were included in our analyses. Phylogenetic analyses revealed five main mitochondrial DNA clades, which were partly confirmed by analyses of the ITS-1 sequences. The genetic differentiation between the clades was found to be in the range p=2.4-11.8%. Most of the populations belonged to clade I, representing Bythinella hansboetersi, and were distributed in SW Bulgaria. Clades II and III inhabit areas adjacent to clade I and were most closely related with the latter clade. Much more distinct were clade V, found at one locality in NW Bulgaria, and clade IV, found at one locality in SE Bulgaria, close to the sea. Four populations were found in caves, but only one of these represented a distinct clade. Considering the observed pattern of interpopulation differentiation of Bythinella in Bulgaria, we can suppose that isolation between clades I, II and III may have been caused by glaciations during the Pleistocene. The time of isolation between the above three clades and clade IV coincides with the Messinian Salinity Crisis, and the time of isolation between the clade V and the other four most probably reflects the isolation of the Rhodopes from western Balkan Mts by the seawater of the Dacic Basin.

No MeSH data available.