The human settlement of the Pacific Islands represents one of the most recent major migration events of mankind. Polynesians originated in Asia according to linguistic evidence or in Melanesia according to archaeological evidence. To shed light on the genetic origins of Polynesians, we investigated over 400 Polynesians from 8 island groups, in comparison with over 900 individuals from potential parental populations of Melanesia, Southeast and East Asia, and Australia, by means of Y chromosome (NRY) and mitochondrial DNA (mtDNA) markers. Overall, we classified 94.1% of Polynesian Y chromosomes and 99.8% of Polynesian mtDNAs as of either Melanesian (NRY-DNA: 65.8%, mtDNA: 6%) or Asian (NRY-DNA: 28.3%, mtDNA: 93.8%) origin, suggesting a dual genetic origin of Polynesians in agreement with the "Slow Boat" hypothesis. Our data suggest a pronounced admixture bias in Polynesians toward more Melanesian men than women, perhaps as a result of matrilocal residence in the ancestral Polynesian society. Although dating methods are consistent with somewhat similar entries of NRY/mtDNA haplogroups into Polynesia, haplotype sharing suggests an earlier appearance of Melanesian haplogroups than those from Asia. Surprisingly, we identified gradients in the frequency distribution of some NRY/mtDNA haplogroups across Polynesia and a gradual west-to-east decrease of overall NRY/mtDNA diversity, not only providing evidence for a west-to-east direction of Polynesian settlements but also suggesting that Pacific voyaging was regular rather than haphazard. We also demonstrate that Fiji played a pivotal role in the history of Polynesia: humans probably first migrated to Fiji, and subsequent settlement of Polynesia probably came from Fiji.

Genetic differences between human populations are typically larger for the Y-chromosome than for mitochondrial DNA (mtDNA), which has been attributed to the ubiquity of patrilocality across human cultures. However, this claim has been disputed, and previous analyses of matrilocal groups give conflicting results. Here we analyse mtDNA variation (complete mtDNA genome sequences via next-generation sequencing) and non-recombining regions of the Y-chromosome variation (Y-single-nucleotide-polymorphisms and Y-short-tandem-repeats (STR)) in a matrilocal group (the Semende) and a patrilocal group (the Besemah) from Sumatra. We find in the Semende significantly lower mtDNA diversity than in the Besemah as expected for matrilocal groups, but unexpectedly we find no difference in Y-chromosome diversity between the groups. We highlight the importance of using complete mtDNA sequences for such analyses, as using only partial sequences (as done in previous studies) can give misleading results.

Global climate change is increasing the range of temperatures that crop plants must face during their life cycle, giving negative effects to yields. In this changing scenario, understanding the genetic control of plant responses to a range of increasing temperature conditions is a prerequisite to developing cultivars with increased resilience. The current work reports the identification of Quantitative Trait Loci (QTL) involved in reproductive traits affected by temperature, such as the flower number (FLN) and fruit number (FRN) per truss and percentage of fruit set (FRS), stigma exsertion (SE), pollen viability (PV) and the incidence of the physiological disorder tipburn (TB).These traits were investigated in 168 Recombinant Inbred Lines (RIL) and 52 Introgression Lines (IL) derived from the cross between Solanum lycopersicum var. "MoneyMaker" and S. pimpinellifolium accession TO-937. Mapping populations were cultivated under increased temperature regimen conditions: T1 (25 • C day/21 • C night), T2 (30 • C day/25 • C night) and T3 (35 • C day/30 • C night). The increase in temperature drastically affected several reproductive traits, for example, FRS in Moneymaker was reduced between 75 and 87% at T2 and T3 when compared to T1, while several RILs showed a reduction of less than 50%. QTL analysis allowed the identification of genomic regions affecting these traits at different temperatures regimens. A total of 22 QTLs involved in reproductive traits at different temperatures were identified by multi-environmental QTL analysis and eight involved in pollen viability traits. Most QTLs were temperature specific, except QTLs on chromosomes 1, 2, 4, 6, and 12. Moreover, a QTL located in chromosome 7 was identified for low incidence of TP in the RIL population, which was confirmed in ILs with introgressions on chromosome 7. Furthermore, ILs with introgressions in chromosomes 1 and 12 had good FRN and FRS in T3 in replicated trials. These results represent a catalog of QTLs and pre-breeding materials that could be used as the starting point for deciphering the genetic control of the genetic response of reproductive traits at different temperatures and paving the road for developing new cultivars adapted to climate change.

Background Due to global warming, the search for new sources for heat tolerance and the identification of genes involved in this process has become an important challenge as of today. The main objective of the current research was to verify whether the heat tolerance determined in controlled greenhouse experiments could be a good predictor of the agronomic performance in field cultivation under climatic high temperature stress. Results Tomato accessions were grown in greenhouse under three temperature regimes: control (T1), moderate (T2) and extreme heat stress (T3). Reproductive traits (flower and fruit number and fruit set) were used to define heat tolerance. In a first screening, heat tolerance was evaluated in 219 tomato accessions. A total of 51 accessions were identified as being potentially heat tolerant. Among those, 28 accessions, together with 10 accessions from Italy (7) and Bulgaria (3), selected for their heat tolerance in the field in parallel experiments, were re-evaluated at three temperature treatments. Sixteen tomato accessions showed a significant heat tolerance at T3, including five wild species, two traditional cultivars and four commercial varieties, one accession from Bulgaria and four from Italy. The 15 most promising accessions for heat tolerance were assayed in field trials in Italy and Bulgaria, confirming the good performance of most of them at high temperatures. Finally, a differential gene expression analysis in pre-anthesis (ovary) and post-anthesis (developing fruit) under heat stress among pairs of contrasting genotypes (tolerant and sensitive from traditional and modern groups) showed that the major differential responses were produced in post-anthesis fruit. The response of the sensitive genotypes included the induction of HSP genes, whereas the tolerant genotype response included the induction of genes involved in the regulation of hormones or enzymes such as abscisic acid and transferases. Conclusions The high temperature tolerance of fifteen tomato accessions observed in controlled greenhouse experiments were confirmed in agronomic field experiments providing new sources of heat tolerance that could be incorporated into breeding programs. A DEG analysis showed the complex response of tomato to heat and deciphered the different mechanisms activated in sensitive and tolerant tomato accessions under heat stress.

La langosta espinosa del Pacífico (Panulirus gracilis) es un importante recurso pesquero del Pacífico Occidental de Panamá. Entre octubre de 2005 y abril de 2007, la población de langosta del Golfo de Montijo se muestreó para determinar LT, LC y LA, el peso total, sexo, desarrollo gonadal y la frecuencia de hembras grávidas. Además, datos de volúmenes de desembarque procedentes del Parque Nacional Marino Golfo de Chiriquí fueron utilizados para estimar la captura por unidad de esfuerzo (CPUE) (kg de langosta desembarcada / pescador-semana) entre los años 2000 y 2009. Para el Golfo de Montijo, la LT (media ± DE.) de las langostas fue de 206 ± 31 mm y las hembras resultaron más grandes y pesadas que los machos. La frecuencia acumulada de la LC y del abdomen indicó que un alto porcentaje de las capturas ocurren por debajo de la talla mínima legal cuando la regulación se aplica por la medida del abdomen (112 mm) y es mayor en machos que en hembras. Esta diferencia es consecuencia de una regulación que no se basó en la morfometría de P. gracilis y de la presunción de que la LA es el doble de la LC. Se observaron hembras con gónadas maduras o con huevos durante todo el periodo de muestreo, lo que indica una reproducción continua. La proporción sexual favoreció a los machos (1.31:1). Entre el 2000 y el 2009 se observó una importante reducción del volumen y de la CPUE.AbstractThe Pacific spiny lobster (Panulirus gracilis) is an important fishery resource from the WesternPacific region of Panama. Between October 2005 and April 2007, the Gulf of Montijo lobsterpopulation was sampled to determine total length (LT), cephalothorax length (LC), abdominallength (LA), total weight, sex, gonadal development, and frequency of gravid females.Furthermore, lobster landing volumes from the Gulf of Chiriquí National Marine Park were usedto estimate the catch per unit effort (CPUE) (kg of lobster landed / fisherman-week) between 2000and 2009. Lobster LT in the Gulf of Montijo (average ± SD) was 206 ± 31 mm and females weresignificantly larger in size and weight than males. The cumulative frequency of cephalothoraxand abdominal lengths indicated that a high percentage of catches occur below the minimumlegal size when regulation is applied measuring the abdomen (112 mm). Incidence of suchcases is greater in males than in females. This difference might be a consequence of a regulationlacking morphometric data for P. gracilis and the assumption that the abdominal length is twicethe cephalothorax length. Females with mature gonads and eggs were observed throughout thesampling period, which is indicative of continuous reproduction. Sex ratio was male biased(1.31:1). Between 2000 and 2009 there was an important reduction in volume and CPUE.