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2.
Heredity (Edinb) ; 115(5): 444-51, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25990877

RESUMEN

Genes with relevant roles in the differentiation of closely-related species are likely to have diverged simultaneously with the species and more accurately reproduce the species tree. The Lusitanian (Microtus lusitanicus) and Mediterranean (M. duodecimcostatus) pine voles are two recently separated sister species with fossorial lifestyles whose different ecological, physiological and morphological phenotypes reflect the better adaptation of M. duodecimcostatus to the underground habitat. Here we asked whether the differentiation of M. lusitanicus and M. duodecimcostatus involved genetic variations within the tumour suppressor p53 gene, given its role in stress-associated responses. We performed a population-genetic analysis through sequencing of exons and introns of p53 in individuals from sympatric and allopatric populations of both the species in the Iberian Peninsula in which a unidirectional introgression of mitochondrial DNA was previously observed. We were able to discriminate the two species to a large extent. We show that M. duodecimcostatus is composed of one genetically unstructured group of populations sharing a P53 protein that carries a mutation in the DNA-binding region not observed in M. lusitanicus, raising the possibility that this mutation may have been central in the evolutionary history of M. duodecimcostatus. Our results provide suggestive evidence for the involvement of a master transcription factor in the separation of M. lusitanicus and M. duodecimcostatus during Microtus radiation in the Quaternary presumably via a differential adaptive role of the novel p53 in M. duodecimcostatus.


Asunto(s)
Arvicolinae/genética , Genes p53 , Variación Genética , Genética de Población , Animales , Arvicolinae/clasificación , ADN Mitocondrial/genética , Evolución Molecular , Exones , Haplotipos , Intrones , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADN , España , Especificidad de la Especie , Simpatría
3.
Heredity (Edinb) ; 109(6): 340-8, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22892639

RESUMEN

In the last few years, dozens of studies have documented the detection of loci influenced by selection from genome scans in a wide range of non-model species. Many of those studies used amplified fragment length polymorphism (AFLP) markers, which became popular for being easily applicable to any organism. However, because they are anonymous markers, AFLPs impose many challenges for their isolation and identification. Most recent AFLP genome scans used capillary electrophoresis (CE), which adds even more obstacles to the isolation of bands with a specific size for sequencing. These caveats might explain the extremely low number of studies that moved from the detection of outlier AFLP markers to their actual isolation and characterization. We document our efforts to characterize a set of outlier AFLP markers from a previous genome scan with CE in ocellated lizards (Lacerta lepida). Seven outliers were successfully isolated, cloned and sequenced. Their sequences are noncoding and show internal indels or polymorphic repetitive elements (microsatellites). Three outliers were converted into codominant markers by using specific internal primers to sequence and screen population variability from undigested DNA. Amplification in closely related lizard species was also achieved, revealing remarkable interspecific conservation in outlier loci sequences. We stress the importance of following up AFLP genome scans to validate selection signatures of outlier loci, but also report the main challenges and pitfalls that may be faced during the process.


Asunto(s)
Análisis del Polimorfismo de Longitud de Fragmentos Amplificados , Lagartos/genética , Repeticiones de Microsatélite/genética , Polimorfismo Genético , Animales , Clonación Molecular , Genoma , Datos de Secuencia Molecular , Selección Genética , Análisis de Secuencia de ADN
4.
J Evol Biol ; 24(10): 2289-98, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21812853

RESUMEN

A comprehensive knowledge on the genetic basis of coloration is crucial to understand how new colour phenotypes arise and how they contribute to the emergence of new species. Variation in melanocortin-1 receptor (Mc1r), a gene that has been reported as a target for repeated evolution in a wide range of vertebrate taxa, was assessed in European ocellated lizards (Lacerta lepida) to search for associations with melanin-based colour phenotypes. Lacerta lepida subspecies' distribution is associated with the three major bio-climatic regions in the Iberian Peninsula. A nonconserved and derived substitution (T162I) was associated with the L. l. nevadensis phenotype (prevalence of brown scales). Another substitution (S172C) was associated with the presence of black scales in both L. l. lepida and L. l. iberica, but no mutations were found to be associated with the higher proportion of black in L. l. iberica. Extensive genotyping of Mc1r along the contact zone between L. l. nevadensis and L. l. lepida revealed low gene flow (only two hybrids detected). The implications of these findings are discussed in the context of previous knowledge about the evolutionary history of ocellated lizards.


Asunto(s)
Variación Genética , Genotipo , Lagartos/genética , Receptor de Melanocortina Tipo 1/genética , Sustitución de Aminoácidos , Animales , Clima , Color , Flujo Génico , Estudios de Asociación Genética , Fenotipo , Análisis de Secuencia de ADN
5.
Mol Phylogenet Evol ; 56(1): 462-7, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20307671

RESUMEN

Philaenus spumarius, widely studied for its colour/pattern polymorphism, is a widespread species across the Holartic. The patterns of haplotype divergence at the mitochondrial gene cytochrome oxidase I (COI) found in this study suggest a postglacial western Europe (Iberian and Italian peninsulas to Britain) and a eastern (from Near East to Finland) south-to-north colonization. The haplotypes found in North America are most likely derived from the British haplotypes. The barcode fragment used here allowed the distinction of the species within genus Philaenus and questioned some taxonomic identifications of sequences present in Genbank.


Asunto(s)
Evolución Molecular , Hemípteros/genética , Filogenia , Análisis de Secuencia de ADN/métodos , Animales , Teorema de Bayes , ADN Mitocondrial/genética , Complejo IV de Transporte de Electrones/genética , Genes de Insecto , Genes Mitocondriales , Haplotipos , Hemípteros/clasificación , Funciones de Verosimilitud , Alineación de Secuencia
6.
Mol Ecol Resour ; 8(6): 1254-5, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21586013

RESUMEN

concatenator is a simple and user-friendly software that implements two very useful functions for phylogenetics data analysis. It concatenates NEXUS files of several fragments in a single NEXUS file ready to be used in phylogenetics software, such as paup and mrbayes and it converts FASTA sequence data files to NEXUS and vice-versa. Additionally, concatenated files can be prepared for partition tests in paup. It is freely available in http://cobig2.fc.ul.pt.

8.
Proc Biol Sci ; 268(1476): 1625-30, 2001 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-11487410

RESUMEN

Ancient climatic fluctuations have caused changes in the demography and distribution of many species. The genetic differentiation between populations of the same species and of sister species is often attributed largely to the more recent Pleistocene fluctuations. Recent interpretations, which implicate earlier episodes, have proved controversial. We address the timing of genetic divergence in the Iberian lizard Lacerta schreiberi by studying the phylogeography of the cytochrome b sequence. The species has a remarkable morphological uniformity, yet our evidence suggests that earlier events in the Pliocene initiated the main divergence between populations. This interpretation implies that the different populations survived through the Pleistocene in separate localities. This conclusion is robust to different molecular clock calibrations. The persistence of earlier differentiation through the Pleistocene has wide implications for our understanding of Pleistocene refugia in this species and, by extension, to the biogeography of the whole region.


Asunto(s)
Lagartos/fisiología , Animales , Evolución Biológica , Clima , Genética de Población
9.
J Trace Elem Electrolytes Health Dis ; 8(2): 119-22, 1994 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-7881277

RESUMEN

To obtain further insight into the role of selenium in the development of atherosclerosis, plasma selenium and lipid parameters were determined in 126 Portuguese subjects living in the region of Lisbon, 60 women and 66 men, 20-60 years old, divided up in to three groups according to their plasma lipid profile: Group I consisted of normolipidemic subjects having plasma triglycerides and total cholesterol < 200mg/dL; Group II was composed of hypercholesteremic subjects with total cholesterol > 200mg/dL and plasma triglycerides < 200mg/dL; Group III was composed of hypercholesteremic and hypertriglyceremic subjects having total cholesterol and plasma triglycerides > 200mg/dL. Respective values for mean plasma selenium (+/- SD) in the groups were: 93 +/- 18 micrograms/L, 90 +/- 17 micrograms/L and 96 +/- 18 micrograms/L. A weak significant difference in plasma selenium between women and men was, however, observed in Group I (87 +/- 20 micrograms/L vs. 100 +/- 11 micrograms/L, p < 0.05). Regression analysis showed no significant relationship between plasma selenium and lipid parameters, except in the most hyperlipidemic women of Group III, where a weak correlation between plasma selenium and the HDL-cholesterol/total cholesterol ratio (r = 0.80, p < 0.05) was observed. The present study suggests that the relationship between selenium and HDL-cholesterol has to be further examined, taking into account nutritional, metabolic and genetic factors.


Asunto(s)
Colesterol/sangre , Selenio/sangre , Triglicéridos/sangre , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Portugal
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