Nucleotide diversity of a ND5 fragment confirms that population expansion is the most suitable explanation for the mtDNA haplotype polymorphism of Drosophila subobscura.
Results from mitochondria (mt) DNA restriction site analyses (RSAs) have revealed that wild populations of Drosophila subobscura are formed by two common (I and II) and some rare, often endemic, low-frequency haplotypes. In the study reported here, we analysed nucleotide diversity in a 942-bp fragment of the mtDNA ND5 gene in 48 D. subobscura individuals captured from three populations that showed haplotypes I, II or the less common ones, as well as in one additional individual belonging to D. guanche that was taken as an outgroup. RSAs and sequencing results were compared. The two approaches yielded similar nucleotide variability parameters, suggesting a consistency in the results obtained from mtDNA dynamics in natural populations of D. subobscura. Patterns of polymorphism at ND5 are most consistent with the hypothesis of population expansion after a bottleneck that may have occurred since the last glaciation or which may occur seasonally after the summer and winter. However, we cannot rule out that selection has a role in maintaining the two major haplotypes at intermediate frequencies in worldwide populations of D. subobscura.
Castro
José A
JA
Laboratori de Genètica, Departament de Biologia, Edifici Guillem Colom, Facultat de Ciències, Universitat de les Illes Balears, Campus de la UIB, Palma de Mallorca 07122, Balearic Islands, Spain. jose.castro@uib.es
Barrio
Eladio
E
González
Ana
A
Picornell
Antònia
A
Ramon
Maria Misericòrdia
MM
Moya
Andrés
A
D000818:Animals; D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics*; D004330:Drosophila / Q000235:genetics*; D005260:Female; D006239:Haplotypes / Q000235:genetics; D008297:Male; D024101:Mitochondrial Proteins / Q000235:genetics*; D009711:Nucleotides / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D011156:Population Density
D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; D009711:Nucleotides