On the Y chromosome of Chennai, Tamil Nadu and the Indian subcontinent.

Several migratory waves from various origins along with cultural practices restricting marriages between people of different castes and tribes as well as continued endogamy have led to a complex and diverse society in the Indian subcontinent. Despite being widely represented in genetic studies, several interrogatives remain with regards to India's current genetic constituents and distributions, source populations and population relationships. To identify the forces that may have shaped Indian population's genetic relationships, we undertook a comprehensive comparative study of the Y-chromosomes across India utilizing Y-STR and Y-SNP chromosomal markers using the general population of Chennai in the state of Tamil Nadu as a point of reference. Our analyses identify differences in source populations for different regions within India, unique linguistic characteristics as well as demographic and cultural forces that may have shaped population structure.

Neolithic expansion and the 17q21.31 inversion in Iberia: an evolutionary approach to H2 haplotype distribution in the Near East and Europe.

The chromosomal region 17q21.31 harbors a 900 kb inversion polymorphism named after the microtubule-associated protein tau (MAPT) gene. Since no recombination occurs, two haplotypes are recognized: a directly oriented variant (H1) and an inverted variant (H2). The H2 haplotype features a distribution pattern with high frequencies in the Near East and Europe, medium levels in South Asia and North Africa, and low levels elsewhere. Studies of this genomic region are relevant owing to its likely association with numerous neurodegenerative diseases. However, the causes underlying the geographic distribution of the haplotype frequencies remain a bone of contention among researchers. With this work, we have intended to outline a plausible hypothesis on the origin of the high European H2 frequencies. To that end, we have analyzed an extensive population database (including three new Iberian populations) to explore potential clinal variations of H2 frequencies. We found a sigmoidal frequency cline with an upward trend from South Asia to Europe. The maximum value was detected in the Basques from Gipuzkoa province (0.494) with the curve's inflection point in the Near East. From our results, we suggest that the most likely scenario for high H2 frequencies in Europe would be a founding event in the Near East during the late Paleolithic or early Neolithic. Subsequently, such H2 overrepresentation would have reached Europe with the arrival of the first Neolithic farmers. The current frequencies and geographic distribution of the 17q21.31 inversion suggest that the founding events mainly affected the H2D subhaplotype.

Systemic inflammation and sympathetic activation in gestational diabetes mellitus with obstructive sleep apnea.

BACKGROUND: Although some evidence suggests an association between obstructive sleep apnea (OSA) and gestational diabetes mellitus (GDM), its consequences still remain largely unknown. We sought to determine whether OSA is associated with higher inflammation and sympathetic levels in GDM, and to relate them with insulin resistance and perinatal outcomes. METHODS: OSA was identified by polysomnography and defined as an apnea-hypopnea index of ≥ 5 h-1. Plasma cytokines (TNF-α, IL-1ß, IL-6, IL-8, IL-10), metanephrine, and normetanephrine were determined by immunoassays. RESULTS: We included 17 patients with GDM and OSA and 34 without OSA. Women with GDM and OSA had higher normetanephrine concentrations [81 IQR (59-134) vs. 68 (51-81) pg/mL]. No differences in the inflammatory profile were found, while IL-1ß was higher in patients with mean nocturnal oxyhemoglobin saturation ≤ 94%. We found positive correlations between increased sympathetic activation and IL-1ß, with obstructive apneas, while time in REM showed an inverse relationship with IL-1ß and metanephrine. Furthermore, IL-10 was inversely related with time in sleep stages 1-2, and with the arousal index, and it was positively related with time in slow-wave sleep. Significant correlations were also found between IL-1ß and insulin resistance. There were no significant differences in neonatal characteristics; however, we found inverse relationships between IL-10 and birth weight (BW), and percentile of BW. CONCLUSIONS: OSA increased sympathetic activity, and IL-1ß concentration was higher in patients with GDM with lower nocturnal oxygenation, all of which were related with obstructive events, and time in REM. Moreover, IL-1ß was related with insulin resistance, and IL-10 inversely correlated with neonatal BW.

Epidemiologic and Economic Analysis of Rapid Antiretroviral Therapy Initiation with Bictegravir/Emtricitabine/Tenofovir Alafenamide in Spain.

OBJECTIVE: This study aimed to assess the potential epidemiological and economic impact of rapid initiation of human immunodeficiency virus (HIV) treatment with bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) on HIV transmission compared with the current initiation observed in clinical practice in Spain. METHODS: A transmission model was adapted to estimate the cumulative HIV infection incidence and potential cost savings based on the number of HIV infections prevented among men who have sex with men, heterosexual males and females, and people who inject drugs (PWID) over a 20-year time horizon. The analysis compared rapid antiretroviral therapy (ART) initiation with B/F/TAF (9 days from diagnosis until treatment initiation) versus current ART initiation practice (with an average of 35 days from diagnosis to treatment). People living with HIV were distributed according to their treatment status. Risk for transmission was assigned to undiagnosed, diagnosed in care and not receiving ART, and receiving ART but virally unsuppressed, which was estimated by sexual contact, needles and syringes shared among PWID, state of HIV infection, and ART use. RESULTS: In the base-case analysis, rapid ART initiation with B/F/TAF is expected to prevent 992 new HIV infections over the next 20 years compared with current ART initiation practices. Considering the lifetime costs of treating HIV infection, the reduction in HIV incidence could result in potential cost savings of €323 million. CONCLUSIONS: These results suggest that rapid ART initiation with B/F/TAF in newly diagnosed patients with HIV is a high-value strategy for the Spanish National Health System and society, reducing HIV incidence and thereby reducing future related direct and indirect costs of care.

Tau (MAPT) haplotypes in Jordan: new evidence on the Middle East as a melting-pot predating Neolithic migration.

Frequencies of H1 and H2 haplotypes of the microtubule-associated protein tau (MAPT) gene were examined in two Jordanian samples. The criterion for haplotype assignment was the presence/absence of the intronic 238-bp deletion, located between exons 9 and 10 of the MAPT genomic region. We further compiled MAPT haplotype frequencies in Middle Eastern, South Asian, and European populations to widen the scope of analyses. Jordan MAPT*H2 haplotype frequencies peaked among worldwide samples analysed to date, with the Jordan general population featuring the top value (0.386). AMOVA tests results indicated spatial genetic structuring, as they unveiled significant differences in H2 frequencies between South Asia and Europe, with a hypothetical contact zone in the Middle East. The southeastern region of the Middle East shares low H2 frequencies with South Asia, while the northwestern area shows high H2 frequencies, similar to and even higher than observed in Europe. We suggest that high H2 frequencies could have originated at the beginning of the Neolithic in the western region of the Middle East, most likely through genetic drift episodes associated with founding events. Subsequently, the arrival of Neolithic farmers boosted the H2 haplotype spreading throughout Europe.

Paternal heritage in Jujuy province (Northwest Argentina): Evidence for sex-biased gene flow and genetic drift effects.

OBJECTIVES: This study aimed to explore the diversity of paternal lineages in Jujuy province (Argentina) by analyzing Y chromosome markers. Furthermore, we examined among-population genetic variability based both on paternally (NRY haplotypes) and maternally (mtDNA haplogroups) inherited markers. We sought to evaluate the impact of sex-biased gene flow on genetic background in Jujuy, and contribute data on the microevolutionary forces acting in this zone. METHODS: DNA from 149 males from five Jujuy regions were analyzed for 12 non-recombining Y (NRY) markers. Genetic heterogeneity among Jujuy regions was evaluated through population differentiation tests. To identify potential genetic boundaries in Jujuy, analysis of molecular variance (AMOVA) and the Monmonier's algorithm implemented in the Barrier v2.2 software were employed. RESULTS: A clear divergence between Jujuy highlands and lowlands for NRY haplotypes was found. A marked discrepancy between genetic structuring for paternal lineages and the lack of geographical pattern for mitogenomes was confirmed by all statistical analyses. CONCLUSIONS: Genetic structuring of paternal lineages is most likely caused by admixture processes that have occurred since colonial times in the Jujuy lowlands. Immigrants were predominantly male that settled in the lower altitude zones, due to the steep orography of the region. Input of allochthonous male lineages because of gene flow toward the lowlands would have increased diversity of NRY markers, thus compensating for drift effects. Likewise, limited input of allochthonous mitogenomes would have promoted genetic drift, a key factor in the shaping of diversity of maternal lineages across Jujuy subpopulations, irrespective of altitude.

Tau haplotypes support the Asian ancestry of the Roma population settled in the Basque Country.

We examined tau haplotype frequencies in two different ethnical groups from the Basque Country (BC): Roma people and residents of European ancestry (general population). In addition, we analyzed the spatial distribution of tau haplotypes in Eurasian populations to explore the genetic affinities of the Romani groups living in Europe in a broader scope. The 17q21.31 genomic region was characterized through the genotyping of two diagnostic single nucleotide polymorphisms, SNPs (rs10514879 and rs199451), which allow the identification of H1 and H2 haplotypes. A significant heterozygous deficit was detected in the Romani for rs10514879. The H2 haplotype frequency proved to be more than twice in the BC general population (0.283) than in the Roma people (0.127). In contrast, H2 frequency proved to be very similar between Basque and Hungarian Romani, and similar to the H2 frequencies found in northwestern India and Pakistan as well. Several statistical analyses unveiled genetic structuring for the MAPT diversity, mirrored in a significant association between geography and genetic distances, with an upward trend of H2 haplotype frequencies from Asia to Europe. Yet, Roma samples did not fit into this general spatial patterning because of their discrepancy between geographical position and H2 frequency. Despite the long spatial coexistence in the Basque region between the residents of European ancestry and the Roma, the latter have preserved their Asian genetic ancestry. Bearing in mind the lack of geographical barriers between both ethnical groups, these findings support the notion that sociocultural mores might promote assortative matings in human populations.

Policaprolactone/polyvinylpyrrolidone/siloxane hybrid materials: Synthesis and in vitro delivery of diclofenac and biocompatibility with periodontal ligament fibroblasts.

In this paper, we report the synthesis of polycaprolactone (PCL) based hybrid materials containing hydrophilic domains composed of N-vinylpyrrolidone (VP), and γ-methacryloxypropyltrimethoxysilane (MPS). The hybrid materials were obtained by RAFT copolymerization of N-vinylpyrrolidone and MPS using a pre-formed dixanthate-end-functionalized PCL as macro-chain transfer agent, followed by a post-reaction crosslinking step. The composition of the samples was determined by elemental and thermogravimetric analyses. Differential scanning calorimetry and X-ray diffraction indicated that the crystallinity of PCL decreases in the presence of the hydrophilic domains. Scanning electron microscopy images revealed that the samples present an interconnected porous structure on the swelling. Compared to PCL, the hybrid materials presented low water contact angle values and higher elastic modulus. These materials showed controlled release of diclofenac, and biocompatibility with human periodontal ligament fibroblasts.

STR Markers Unveil Microgeographic Differentiation over the Steep Mountainous Landscape of Jujuy Province, Northwest Argentina.

This study explores potential signals of microdifferentiation in the gene pool of three high-altitude populations from Jujuy province in northwest Argentina using highly polymorphic markers. These human communities are characterized by extreme living conditions and very low population densities owing to considerable height above sea level and steep orography. A set of autosomal short tandem repeats (STRs) located at chromosome 6 (6p21.3) was typed in samples from Quebrada Baja (∼2,500 m), Quebrada Alta (∼3,300 m), and Puna (> 3,500 m). Genetic diversity was estimated through the observed and expected heterozygosities and the haplotype diversity. Analyses of the molecular variance (AMOVAs) and population differentiation tests based on allele and haplotype frequencies were performed to assess genetic heterogeneity among subgroups. No deviation from Hardy-Weinberg equilibrium was detected in any subpopulation, yet significant departures were detected in the analysis considering the whole area (D6S2792 and D6S105 loci). Overall, genetic diversity showed a decreasing trend as the altitude increased. Thus, allele and haplotype frequencies showed the most significant differences between Puna and Quebrada Baja, the populations sited at the edges of the altitude range. The trend toward reduction of heterozygosity with altitude is compatible with historical patterns of colonization, interregional migration trends, population density, and genetic admixture. The main consequence of the complex mountainous landscape of Jujuy would be an imbalance in the interplay of gene flow and genetic drift, favoring the latter. The combined effect of restricted gene flow and intense genetic drift would have promoted local genetic differentiation between the Jujuy highland subpopulations, leading to spatial patterning of the allele frequencies not entirely attributable to geographic distance. Our findings corroborate the effectiveness of STRs to identify microevolutionary changes.

The expanded mtDNA phylogeny of the Franco-Cantabrian region upholds the pre-neolithic genetic substrate of Basques.

The European genetic landscape has been shaped by several human migrations occurred since Paleolithic times. The accumulation of archaeological records and the concordance of different lines of genetic evidence during the last two decades have triggered an interesting debate concerning the role of ancient settlers from the Franco-Cantabrian region in the postglacial resettlement of Europe. Among the Franco-Cantabrian populations, Basques are regarded as one of the oldest and more intriguing human groups of Europe. Recent data on complete mitochondrial DNA genomes focused on macrohaplogroup R0 revealed that Basques harbor some autochthonous lineages, suggesting a genetic continuity since pre-Neolithic times. However, excluding haplogroup H, the most representative lineage of macrohaplogroup R0, the majority of maternal lineages of this area remains virtually unexplored, so that further refinement of the mtDNA phylogeny based on analyses at the highest level of resolution is crucial for a better understanding of the European prehistory. We thus explored the maternal ancestry of 548 autochthonous individuals from various Franco-Cantabrian populations and sequenced 76 mitogenomes of the most representative lineages. Interestingly, we identified three mtDNA haplogroups, U5b1f, J1c5c1 and V22, that proved to be representative of Franco-Cantabria, notably of the Basque population. The seclusion and diversity of these female genetic lineages support a local origin in the Franco-Cantabrian area during the Mesolithic of southwestern Europe, ~10,000 years before present (YBP), with signals of expansions at ~3,500 YBP. These findings provide robust evidence of a partial genetic continuity between contemporary autochthonous populations from the Franco-Cantabrian region, specifically the Basques, and Paleolithic/Mesolithic hunter-gatherer groups. Furthermore, our results raise the current proportion (≈ 15%) of the Franco-Cantabrian maternal gene pool with a putative pre-Neolithic origin to ≈ 35%, further supporting the notion of a predominant Paleolithic genetic substrate in extant European populations.

Young Alu insertions within the MHC class I region in native American populations: insights into the origin of the MHC-Alu repeats.

OBJECTIVES: Genetic heterogeneity of two Amerindian populations (Jujuy province, Argentina, and Waorani tribe, Ecuador) was characterized by analyzing data on polymorphic Alu insertions within the human major histocompatibility complex (MHC) class I region (6p21.31), which are completely nonexistent in Native Americans. We further evaluated the haplotype distribution and genetic diversity among continental ancestry groups and their potential implications for the dating of the origin of MHC-Alus. METHODS: Five MHC-Alu elements (AluMicB, AluTF, AluHJ, AluHG, and AluHF) were typed in samples from Jujuy (N = 108) and Waorani (N = 36). Allele and haplotype frequency data on worldwide populations were compiled to explore spatial structuring of the MHC-Alu diversity through AMOVA tests. We utilized the median-joining network approach to illustrate the continental distribution of the MHC-Alu haplotypes and their phylogenetic relationships. RESULTS: Allele and haplotype distributions differed significantly between Jujuy and Waorani. The Waorani featured a low average heterozygosity attributable to strong population isolation. Overall, Alu markers showed great genetic heterogeneity both within and among populations. The haplotype distribution was distinctive of each continental ancestry group. Contrary to expectations, Africans showed the lowest MHC-Alu diversity. CONCLUSIONS: Genetic drift mainly associated to population bottlenecks seems to be reflected in the low MHC-Alu diversity of the Amerindians, mainly in Waorani. Geographical structuring of the haplotype distribution supports the efficiency of the MHC-Alu loci as lineage (ancestry) markers. The markedly low Alu diversity of African populations relative to other continental clusters suggests that these MHC-Alus might have arisen after the anatomically modern humans expanded out of Africa.

Mitochondrial DNA control region data reveal high prevalence of Native American lineages in Jujuy province, NW Argentina.

Mitochondrial control region (16024-576) sequences were generated from 180 individuals of four population nuclei from the province of Jujuy (NW Argentina), located at different altitudes above sea level. The frequency at which a randomly selected mtDNA profile would be expected to occur in the general population (random match probability) was estimated at 0.011, indicating a relatively high diversity. Analysis of the haplogroup distribution revealed that Native American lineages A2 (13.9%), B (56.7%), C1 (17.8%), D1 (8.9%) and D4h3a (1.1%) accounted for more than 98% of the total mtDNA haplogroup diversity in the sample examined. We detected a certain degree of genetic heterogeneity between two subpopulations located at different points along the altitudinal gradient (Valles and Puna), suggesting that altitude above sea level cannot be ruled out as a factor promoting divergences in mtDNA haplogroup frequencies, since altitude is closely associated with human living conditions, and consequently, with low demographic sizes and the occurrence of genetic drift processes in human communities. In all, mitochondrial DNA database obtained for Jujuy province strongly points to the need for creating local mtDNA databases, to avoid bias in forensic estimations caused by genetic substructuring of the populations.

Ancestry markers from the human chromosome 6: Alu repeats from the MHC in autochthonous Basques.

Polymorphic Alu insertions from the MHC class I region were analyzed in 215 autochthonous Basques from Guipuzcoa and Navarre provinces, with the aim of contributing new MHC Alu data in European ancestry populations. We also seek to assess both the genetic position of native Basques among worldwide samples and the efficiency of the MHC Alu elements as ancestry informative markers (AIMs). According to the MDS and AMOVA results, worldwide populations included in the comparative analyses were grouped in three major clusters defined by genetic ancestry (Africans, Asians and Europeans). The δ values (differences in weighted allele frequencies) among ancestry groups indicated that Alu elements within the alpha-block (AluHF, AluHJ and AluHG) showed an adequate resolving power to discriminate appropriately between some of the major ancestry groups. Alpha block Alu were also revealing of the exceptionality of Basques, as they allowed for the detection of genetic heterogeneity even between Basques and the other Iberian collection considered in the analysis (Valencia). Thus, analysis of the Alu loci within the alpha-block may represent a reliable, informative and cost-effective method to explore the ancestry, geographic origins and demographic history of human populations, which can be very helpful for studies into epidemiological, forensic or evolutionary perspectives.

Alu polymorphisms in the Waorani tribe from the Ecuadorian Amazon reflect the effects of isolation and genetic drift.

OBJECTIVES: The Amazon basin is inhabited by some of the most isolated human groups worldwide. Among them, the Waorani tribe is one of the most interesting Native American populations from the anthropological perspective. This study reports a genetic characterization of the Waorani based on autosomal genetic loci. METHODS: We analyzed 12 polymorphic Alu insertions in 36 Waorani individuals from different communal longhouses settled in the Yasuní National Park. RESULTS: The most notable finding was the strikingly reduced genetic diversity detected in the Waorani, corroborated by the existence of four monomorphic loci (ACE, APO, FXIIIB, and HS4.65), and of other four Alu markers that were very close to the fixation for the presence (PV92 and D1) or the absence (A25 and HS4.32) of the insertion. Furthermore, results of the centroid analysis supported the notion of the Waorani being one of the Amerindian groups less impacted by gene flow processes. CONCLUSIONS: The prolonged isolation of the Waorani community, in conjunction with a historically low effective population size and high inbreeding levels, have resulted in the drastic reduction of their genetic diversity, because of the effects of severe genetic drift. Recurrent population bottlenecks most likely determined by certain deep-rooted sociocultural practices of the Waorani (characterized by violence, internal quarrels, and revenge killings until recent times) are likely responsible for this pattern of diversity. The findings of this study illustrate how sociocultural factors can shape the gene pool of human populations.

The maternal legacy of Basques in northern navarre: New insights into the mitochondrial DNA diversity of the Franco-Cantabrian area.

Autochthonous Basques are thought to be a trace from the human population contraction that occurred during the Last Glacial Maximum, based mainly on the salient frequencies and coalescence ages registered for haplogroups V, H1, and H3 of mitochondrial DNA in current Basque populations. However, variability of the maternal lineages still remains relatively unexplored in an important fraction of the Iberian Basque community. In this study, mitochondrial DNA diversity in Navarre (North Spain) was addressed for the first time. To that end, HVS-I and HVS-II sequences from 110 individuals were examined to identify the most relevant lineages, including analysis of coding region SNPs for the refinement of haplogroup assignment. We found a prominent frequency of subhaplogroup J1c (11.8%) in Navarre, coinciding with previous studies on Basques. Subhaplogroup H2a5, a putative autochthonous Basque lineage, was also observed in Navarre, pointing to a common origin of current Basque geographical groups. In contrast to other Basque subpopulations, comparative analyses at Iberian and European scales revealed a relevant frequency of subhaplogroup H3 (10.9%) and a frequency peak for U5b (15.5%) in Navarre. Furthermore, we observed low frequencies for maternal lineages HV0 and H1 in Navarre relative to other northern Iberian populations. All these findings might be indicative of intense genetic drift episodes generated by population fragmentation in the area of the Franco-Cantabrian refuge until recent times, which could have promoted genetic microdifferentiation between the different Basque subpopulations.

Microevolutionary processes due to landscape features in the province of Jujuy (Argentina).

OBJECTIVES: We seek to evaluate the influence of a diverse and rugged physical environment on the genetic background of human populations. METHODS: We analyzed eight polymorphic Alu insertions in 226 individuals from Jujuy province (Argentina), which is composed of several regions with well-defined geographical features and marked contrasts between them associated with differences in altitude (range: 700-3300 m). This regional division was used to assess the spatial variation of the Alu diversity. RESULTS: Deviations from Hardy-Weinberg Equilibrium expectations resulting from heterozygous deficit were found for FXIIIB and PV92 in the highest subpopulations. Several Alu elements showed genetic heterogeneity between the highest region (La Puna) and the lowest regions (Valle and Selva). Similarly, a decreasing trend of the average heterozygosity according to altitude was found. Both the centroid method and the admixture analysis unveiled a gene flow above the average in lowland populations, indicating a higher proportion of foreign genes introduced by immigrants of European and African ancestry. Furthermore, several Alu frequency clines fitting the orientation of the altitude gradient were detected. CONCLUSIONS: Our study reveals a spatial patterning of the Alu diversity in Jujuy, most likely determined by disparities in landscape and environmental features between the different subregions. Differences in the physical environment would have drastically reduced the homogenizing effects of the gene flow and would have promoted genetic drift episodes in the highest subpopulations. Microevolutionary processes detected in Jujuy have played an important role in the shaping of the gene pool of the populations from this sub-Andean zone from Argentina.

Genetic admixture estimates by Alu elements in Afro-Colombian and Mestizo populations from Antioquia, Colombia.

AIM: This work was intended to gain insights into the admixture processes occurring in Latin American populations by examining the genetic profiles of two ethnic groups from Antioquia (Colombia). SUBJECTS AND METHODS: To analyse the genetic variability, eight Alu insertions were typed in 64 Afro-Colombians and a reference group of 34 Hispanics (Mestizos). Admixture proportions were estimated using the Weighted Least Squares and the Gene Identity methods. The usefulness of the Alu elements as Ancestry Informative Markers (AIMs) was evaluated through differences in weighted allelic frequencies (delta values) and by hierarchical analysis of the molecular variance (AMOVA). RESULTS: The Afro-Colombian gene pool was largely determined by the African component (88.5-88.8%), but the most prominent feature was the null contribution of European genes. Mestizos were characterized by a major European component (60.0-63.8%) and a comparatively low proportion of Amerindian (19.2-20.7%) and African (17.0-19.3%) genes. Five of the Alu loci examined (ACE, APO, FXIIIB, PV92 and TPA25) showed an adequate resolving power to differentiate between continental groups, as indicated by delta values and AMOVA results. CONCLUSIONS: The peculiarity of the Afro-Colombian gene pool seems to be associated with intense genetic drift episodes that occurred in isolated communities founded by small groups of runaway slaves. ACE, APO, FXIIIB, PV92 and TPA25 could be efficiently utilized in studies dealing with demographic history and biogeographical ancestry in human populations.

An evolutionary approach to the high frequency of the Delta F508 CFTR mutation in European populations.

The diffusion of the cattle pastoralism across Europe during the Neolithic period was probably accompanied by the emergence and spread of diverse contagious diseases that were unknown in the Paleolithic and that would have affected the frequency of genes directly or indirectly associated with differential susceptibility and/or resistance to infectious pathogens. We therefore propose that the high frequency of the CFTR gene, and in particular, the common Delta F508 allele mutation in current European and European-derived populations might be a consequence of the impact of selective pressures generated by the transmission of pathogenic agents from domesticated animals, mainly bovine cattle, to the man. Intestinal infectious diseases were probably a major health problem for Neolithic peoples. In such a context, a gene mutation that conferred an increased resistance to the diseases caused by pathogens transmitted by dairy cattle would have constituted a definite selective advantage, particularly in those human groups where cow's milk became an essential component of the diet. This selective advantage would be determined by an increased resistance to Cl(-)-secreting diarrheas of those individuals carrying a single copy of the Delta F508 CFTR mutation (heterozygote resistance). This hypothesis is supported by the strong association between the geography of the diffusion of cattle pastoralism (assessed indirectly by the lactase persistence distribution), the geographic distribution of a sizeable number of HLA alleles (as indicative of potential selective pressures generated by epidemic mortality) and the geographic distribution of the most common mutation causing cystic fibrosis (Delta F508). The systematic interaction of humans with infectious pathogens would have begun in northern Europe, among the carriers of the Funnel Beaker Culture, the first farmers of the North European plain, moving progressively to the south with the dissemination of the cattle pastoralism. This gradual exposure to epidemic mortality among populations located further and further south in Europe as cattle pastoralism expanded could have generated differences in CFTR gene frequencies, thereby shaping the latitudinal frequency gradients observed in present-day European populations.

[Limits of laparoscopic surgery in the treatment of renal tumors]. / Límites de la cirugía laparoscópica en el tratamiento del tumor renal.

Laparoscopic radical nephrectomy is considered to be the technique of choice in the mangement of stage T1 and T2 renal cancer, though increased mastery of this alternative type of surgery has served to expand its indications. In any case, these procedures have a series of limitations which are tied to the intrinsic characteristics of laparoscopic surgery, and which are associated with the patient and tumor characteristics, and the experience of the surgeon. The present study discusses the different indications and establishes the current limits of laparoscopic surgery applied to the management of renal tumors. Its role in cell-reducing therapy in metastatic disease, and the methods available for reducing tumor implantation in the surgical ports are also commented.

Límites de la cirugía laparoscópica en el tratamiento del tumor renal / Limits of laparoscopic surgery in the treatment of renal tumors

Actualmente se considera la nefrectomía radical laparoscópica como la técnica de elección en el tratamiento del cáncer renal en estadios T1 y T2, aunque el dominio de este tipo de alternativa quirúrgica han ido ampliando sus indicaciones. De todas formas existen límites a este tipo de técnicas que van ligadas a la propia idiosincrasia de la laparoscópica; límites que están en relación con las características del paciente, las características del tumor y la experiencia del cirujano. Se discuten las distintas indicaciones y se establecen los límites actuales de la cirugía laparoscópica en el tratamiento del tumor renal, así como su papel en la terapia citoreductora en enfermedad metastásica y los métodos para disminuir el implante tumoral en los puertos de entrada (AU)

Laparoscopic radical nephrectomy is considered to be the technique of choice in the mangement of stage T1 and T2 renal cancer, though increased mastery of this alternative type of surgery has served to expand its indications. In any case, these procedures have a series of limitations which are tied to the intrinsic characteristics of laparoscopic surgery, and which are associated with the patient and tumor characteristics, and the experience of the surgeon. The present study discusses the different indications and establishes the current limits of laparoscopic surgery applied to the management of renal tumors. Its role in cell-reducing therapy in metastatic disease, and the methods available for reducing tumor implantation in the surgical ports are also commented (AU)