ENVIRONMENTAL STRESS AND MUTAGENESIS IN ENTERIC AND NON-ENTERIC BACTERIA

Mutations are fundamental for evolution. For many years it has been thought that mutagenesis occurs only in dividing cells. Now it is clear that mutations arise in non-dividing or slowly dividing microorganisms. Natural populations spend most of the time in stressful environments where their growth rate is highly reduced. Thus, the existence of a mutagenesis process, independent of multiplication (stress-induced mutagenesis, SIM), might have a profound evolutionary role. In the presented paper we review the stateof-the-art in enteric and non-enteric bacteria. We describe different experimental systems as well as the mechanisms and models presented to explain the huge amount of data obtained in more than twenty years of research

Uniparental genetic systems: a male and a female perspective in the domestic cattle origin and evolution

Over the last 20 years, the two uniparentally inherited marker systems, namely mitochondrial DNA and Y chromosome have been widely employed to solve questions about origin and prehistorical range expansions, demographic processes, both in humans and domestic animals. The mtDNA and the Y chromosome, with their unique patterns of inheritance, continue to be extremely important source of information. These markers played significant roles in farm animals in the evaluation of the genetic variation within- and among-breed strains and lines and have widely applied in the fields of linkage mapping, paternity tests, prediction of breeding values in genome-assisted selection, analysis of genetic diversity within breeds detection of population admixture, assessment of inbreeding and relationships between breeds, and assignment of individuals to their breed of origin. This approach offers a unique opportunity to save genetic resources and achieving improved productivity. In the past years, significant progress was achieved in reconstructing detailed cattle phylogenies; many studies indicated multiple parental sources and several levels of phylogeographic structuring. More detailed researches are still in progress in order to provide a more comprehensive picture of such extant variability. This paper is focused on reviewing the use of the two uniparental markers as valuable tool for the characterization of cattle genetic diversity. Furthermore, their implications in animal breeding, management and genetic resources conservation are also reported

Tuber mesentericum and Tuber aestivum Truffles: New Insights Based on Morphological and Phylogenetic Analyses

Tuber aestivum, one of the most sought out and marketed truffle species in the world, is morphologically similar to Tuber mesentericum, which is only locally appreciated in south Italy and north-east France. Because T. aestivum and T. mesentericum have very similar ascocarp features, and collection may occur in similar environments and periods, these two species are frequently mistaken for one another. In this study, 43 T. aestivum and T. mesentericum ascocarps were collected in Italy for morphological and molecular characterization. The morphological and aromatic characteristics of the fresh ascocarps were compared with their spore morphology. Afterwards, we amplified and sequenced the elongation factor 1-α (EF1α) locus and built maximum likelihood trees to assess phylogenetic similarities between the two species. Tuber aestivum and T. mesentericum sequences cluster into different clades, with T. mesentericum sequences divided into three different sub-clades. According to their morphological features, three samples (T7, T8 and T12) were classified as T. mesentericum. However, when fresh, these ascocarps lacked the typical phenolic aromatic note. These specimens fall into the sub-clade III of the T. mesentericum phylogeny, which has the lowest genetic distance from the T. aestivum clade

On the origin and diversification of Podolian cattle breeds: testing scenarios of European colonization using genome-wide SNP data

During the Neolithic expansion, cattle accompanied humans and spread from their domestication centres to colonize the ancient world. In addition, European cattle occasionally intermingled with both indicine cattle and local aurochs resulting in an exclusive pattern of genetic diversity. Among the most ancient European cattle are breeds that belong to the so-called Podolian trunk, the history of which is still not well established. Here, we used genome-wide single nucleotide polymorphism (SNP) data on 806 individuals belonging to 36 breeds to reconstruct the origin and diversification of Podolian cattle and to provide a reliable scenario of the European colonization, through an approximate Bayesian computation random forest (ABC-RF) approach

Helena’s Many Daughters: More Mitogenome Diversity behind the Most Common West Eurasian mtDNA Control Region Haplotype in an Extended Italian Population Sample

The high number of matching haplotypes of the most common mitochondrial (mt)DNA lineages are considered to be the greatest limitation for forensic applications. This study investigates the potential to solve this constraint by massively parallel sequencing a large number of mitogenomes that share the most common West Eurasian mtDNA control region (CR) haplotype motif (263G 315.1C 16519C). We augmented a pilot study on 29 to a total of 216 Italian mitogenomes that represents the largest set of the most common CR haplotype compiled from a single country. The extended population sample confirmed and extended the huge coding region diversity behind the most common CR motif. Complete mitogenome sequencing allowed for the detection of 163 distinct haplotypes, raising the power of discrimination from 0 (CR) to 99.6% (mitogenome). The mtDNAs were clustered into 61 named clades of haplogroup H and did not reveal phylogeographic trends within Italy. Rapid individualization approaches for investigative purposes are limited to the most frequent H clades of the dataset, viz. H1, H3, and H7

The initial peopling of the Americas: a growing number of founding mitochondrial genomes from Beringia

Pan-American mitochondrial DNA (mtDNA) haplogroup C1 has been recently subdivided into three branches, two of which (C1b and C1c) are characterized by ages and geographical distributions that are indicative of an early arrival from Beringia with Paleo-Indians. In contrast, the estimated ages of C1d—the third subset of C1—looked too young to fit the above scenario. To define the origin of this enigmatic C1 branch, we completely sequenced 63 C1d mitochondrial genomes from a wide range of geographically diverse, mixed, and indigenous American populations. The revised phylogeny not only brings the age of C1d within the range of that of its two sister clades, but reveals that there were two C1d founder genomes for Paleo-Indians. Thus, the recognized maternal founding lineages of Native Americans are at least 15, indicating that the overall number of Beringian or Asian founder mitochondrial genomes will probably increase extensively when all Native American haplogroups reach the same level of phylogenetic and genomic resolution as obtained here for C1d.Fil: Perego, Ugo A.. Soreson Molecular Genealogy Foundation; Estados Unidos. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Angerhofer, Norman. Soreson Molecular Genealogy Foundation; Estados UnidosFil: Pala, Maria. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Olivieri, Anna. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Lancioni, Hovirag. Universita Di Perugia; ItaliaFil: Kashani, Baharak Hooshiar. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Carossa, Valeria. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Ekins, Jayne E.. Soreson Molecular Genealogy Foundation; Estados UnidosFil: Gómez Carballa, Alberto. Universidad de Santiago de Compostela; EspañaFil: Huber, Gabriela. Universidad de Innsbruck; AustriaFil: Zimmermann, Bettina. Universidad de Innsbruck; AustriaFil: Corach, Daniel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Servicio de Huellas Digitales Genéticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Babudri, Nora. Universita Di Perugia; ItaliaFil: Panara, Fausto. Universita Di Perugia; ItaliaFil: Myres, Natalie M.. Soreson Molecular Genealogy Foundation; Estados UnidosFil: Parson, Walther. Universidad de Innsbruck; AustriaFil: Semino, Ornella. Università di Pavia. Dipartimento di Genetica e Microbiologia; ItaliaFil: Salas, Antonio. Universidad de Santiago de Compostela; EspañaFil: Woodward, Scott R.. Soreson Molecular Genealogy Foundation; Estados UnidosFil: Achilli, Alessandro. Università di Pavia. Dipartimento di Genetica e Microbiologia; Italia. Universita Di Perugia; ItaliaFil: Torroni, Antonio. Università di Pavia. Dipartimento di Genetica e Microbiologia; Itali

Genetic variability assessment in different Mediterranean canine breeds using microsatellite markers

The domestic dog (Canis familiaris) was the first species to be domesticated. Today, the ‘Fédération Cynologique Internationale’ distinguishes and recognises 360 canine breeds, classified in 10 ethnological groups. Group 5 ‘Spitz and primitive type’ is subdivided into 7 sections. The Kelb tal Fenech (KTF) is allocated in section 6, while section 7 includes the Italian breed Cirneco dell’Etna (CIE) and different breeds (Valenciano, Ibicenco, Canario, Andaluz) of the Spanish Podenco (POD).peer-reviewe

The Mitogenome Relationships and Phylogeography of Barn Swallows (Hirundo rustica)

The barn swallow (Hirundo rustica) poses a number of fascinating scientific questions, including the taxonomic status of postulated subspecies. Here, we obtained and assessed the sequence variation of 411 complete mitogenomes, mainly from the European H. r. rustica, but other subspecies as well. In almost every case, we observed subspecies-specific haplogroups, which we employed together with estimated radiation times to postulate a model for the geographical and temporal worldwide spread of the species. The female barn swallow carrying the Hirundo rustica ancestral mitogenome left Africa (or its vicinity) around 280 thousand years ago (kya), and her descendants expanded first into Eurasia and then, at least 51 kya, into the Americas, from where a relatively recent (<20 kya) back migration to Asia took place. The exception to the haplogroup subspecies specificity is represented by the sedentary Levantine H. r. transitiva that extensively shares haplogroup A with the migratory European H. r. rustica and, to a lesser extent, haplogroup B with the Egyptian H. r. savignii. Our data indicate that rustica and transitiva most likely derive from a sedentary Levantine population source that split at the end of the Younger Dryas (YD) (11.7 kya). Since then, however, transitiva received genetic inputs from and admixed with both the closely related rustica and the adjacent savignii. Demographic analyses confirm this species' strong link with climate fluctuations and human activities making it an excellent indicator for monitoring and assessing the impact of current global changes on wildlife

Whole mitochondrial genomes unveil the impact of domestication on goat matrilineal variability

Background: The current extensive use of the domestic goat (Capra hircus) is the result of its medium size and high adaptability as multiple breeds. The extent to which its genetic variability was influenced by early domestication practices is largely unknown. A common standard by which to analyze maternally-inherited variability of livestock species is through complete sequencing of the entire mitogenome (mitochondrial DNA, mtDNA). Results: We present the first extensive survey of goat mitogenomic variability based on 84 complete sequences selected from an initial collection of 758 samples that represent 60 different breeds of C. hircus, as well as its wild sister species, bezoar (Capra aegagrus) from Iran. Our phylogenetic analyses dated the most recent common ancestor of C. hircus to ~460,000 years (ka) ago and identified five distinctive domestic haplogroups (A, B1, C1a, D1 and G). More than 90 % of goats examined were in haplogroup A. These domestic lineages are predominantly nested within C. aegagrus branches, diverged concomitantly at the interface between the Epipaleolithic and early Neolithic periods, and underwent a dramatic expansion starting from ~12–10 ka ago. Conclusions: Domestic goat mitogenomes descended from a small number of founding haplotypes that underwent domestication after surviving the last glacial maximum in the Near Eastern refuges. All modern haplotypes A probably descended from a single (or at most a few closely related) female C. aegagrus. Zooarchaelogical data indicate that domestication first occurred in Southeastern Anatolia. Goats accompanying the first Neolithic migration waves into the Mediterranean were already characterized by two ancestral A and C variants. The ancient separation of the C branch (~130 ka ago) suggests a genetically distinct population that could have been involved in a second event of domestication. The novel diagnostic mutational motifs defined here, which distinguish wild and domestic haplogroups, could be used to understand phylogenetic relationships among modern breeds and ancient remains and to evaluate whether selection differentially affected mitochondrial genome variants during the development of economically important breeds