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Lombardy, in northern Italy, is the most populated and industrialized Italian region. We attempt to study its genetic structure with two independent sets of data: HLA allele frequencies and surnames. According to our results, it is plausible to deduce that ancient history, more than genetic isolation and drift, may have contributed to the present genetic structure of Lombardy. The hypothesis seems to be confirmed by the results of the cluster analysis of the 11 provinces of the region, which was performed using two different types of markers. Both genes and surnames show approximately the same structure. Not only Celts but also ancient Ligurians (and Etruscans) probably shaped the region into the present three clusters in which the 11 provinces appear to be genetically structured. In particular, an ancient historic, archaeological, and linguistic boundary, along the Adda River, seems to be preserved in present-day Lombardy's population structure.Am. J.Hum. Biol. 19:311–318, 2007. © 2007 Wiley-Liss, Inc.

As a result of their rapid expansion and large larval host range, true fruit flies are among the world's most important agricultural pest species. Among them, Ceratitis capitata has become a model organism for studies on colonization and invasion processes. The genetic aspects of the medfly invasion process have already been analysed throughout its range, with the exception of Australia. Bioinvasion into Australia is an old event: medfly were first captured in Australia in 1895, near Perth. After briefly appearing in Tasmania and the eastern states of mainland Australia, medfly had disappeared from these areas by the 1940s. Currently, they are confined to the western coastal region. South Australia seems to be protected from medfly infestations both by the presence of an inhospitable barrier separating it from the west and by the limited number of transport routes. However, numerous medfly outbreaks have occurred since 1946, mainly near Adelaide. Allele frequency data at 10 simple sequence repeat loci were used to study the genetic structure of Australian medflies, to infer the historical pattern of invasion and the origin of the recent outbreaks. The combination of phylogeographical analysis and Bayesian tests showed that colonization of Australia was a secondary colonization event from the Mediterranean basin and that Australian medflies were unlikely to be the source for the initial Hawaiian invasion. Within Australia, the Perth area acted as the core range and was the source for medfly bioinvasion in both Western and South Australia. Incipient differentiation, as a result of habitat fragmentation, was detected in some localized areas at the periphery of the core range.

The Mediterranean fruit fly, Ceratitis capitata, is a destructive agricultural pest with a long history of invasion success. This pest has been affecting different regions of the United States for the past 30 years, but a number of studies of medfly bioinfestations has focused on the situation in California. Although some progress has been made in terms of establishing the origin of infestations, the overall status of this pest in this area remains controversial. Specifically, do flies captured over the years represent independent infestations or the persistence of a resident population? We present an effort to answer this question based on the use of multilocus genotyping. Ten microsatellite loci were used to analyse 109 medflies captured in several infestations within California between 1992 and 1998. Using these same markers, 242 medflies from regions of the world having 'established' populations of this pest including Hawaii, Guatemala, El Salvador, Ecuador, Brazil, Argentina and Peru, were also analysed. Although phylogenetic analysis, amova analysis, the IMMANC assignment test and geneclass exclusion test analysis suggest that some of the medflies captured in California are derived from independent invasion events, analysis of specimens from the Los Angeles basin provides support for the hypothesis that an endemic population, probably derived from Guatemala, has been established.

A total of forty-three simple sequence repeats (SSRs) were identified in the Mediterranean fruit fly (medfly) Ceratitis capitata. The most common SSR was the dinucleotide (TG)n/(CA)n occurring in thirty of the forty-three microsatellite loci. Polymorphism at ten dinucleotide markers was investigated in 122 flies from six natural populations sampled in the native and colonized areas. A very high level of allelic diversity was detected in the species range. An average of 13.6 alleles was found over all the ten loci indicating the informativeness of SSRs as genetic markers for the medfly. The distribution of microsatellite polymorphism in the species range reflects the medfly colonization history.

The exon-primed intron-crossing (EPIC) PCR technique was used to analyse the size variation at the first intron of the Ceratitis capitata Adh1 gene. A total of 27 samples from 16 natural populations was analysed from five geographical regions in the species range: Africa, Mediterranean Basin, Latin America, Hawaii and Australia. The Adh1 first intron varies extensively in length with at least 18 size variants ranging from 1400 bp to 3450 bp. These variants can be grouped into four distinct size categories: short, medium, long and very long. The majority of these variants are present only in the African populations. Only a subset of the ancestral variants appear to have succeeded in migrating from Africa during the medfly colonization process. The medfly population structure inferred from the intron size polymorphism is congruent with that observed from the analysis of allozyme variation. The geographical dispersal of the medfly from its source area is associated with a gradual and great reduction in intron variability which parallels the trend of decreasing variability evaluated at 26 biochemical loci. The intron phylogenetic tree is in agreement with allozyme data in portraying the dynamic population history of the medfly. Stochastic evolutionary forces such as drift, bottleneck effects and migration seem to have played the major roles in the dispersion pattern of Adh1 intron variation during the colonization of the medfly.