The number of vertebrae is associated with body size and meat production in pigs. To identify quantitative trait loci (QTL) for the number of vertebrae, phenotypic values were measured in 1029 individuals from a White Duroc × Chinese Erhualian intercross F(2) population. A whole genome scan was performed with 194 microsatellite markers in the F(2) population. Four genome-wide significant QTL and eight chromosome-wide significant QTL for the number of vertebrae were identified on pig chromosomes (SSC) 1, 2, 6, 7, 10 and 12. The most significant QTL was detected on SSC7 with a confidence interval of 1 cM, explaining 42.32% of the phenotypic variance in the thoracic vertebral number. The significant QTL on SSC1, 2 and 7 confirmed previous reports. A panel of 276 animals representing seven Western and Chinese breeds was genotyped with 34 microsatellite markers in the SSC7 QTL region. No obvious selective sweep effect was observed in the tested breeds, indicating that intensive selection for enlarged body size in Western commercial breeds did not wipe out the genetic variability in the QTL region. The Q alleles for increased vertebral number originated from both Chinese Erhualian and White Duroc founder animals. A haplotype block of approximately 900 kb was found to be shared by all Q-bearing chromosomes of F(1) sires except for one distinct Q chromosome. The critical region harbours the newly reported VRTN gene associated with vertebral number. Further investigations are required to confirm whether VRTN or two other positional candidate genes, PROX2 and FOS, cause the QTL effect.

Feeding efficiency is a multifactorial and economically important trait in pigs. Genetic improvement of feeding efficiency will greatly benefit the pig industry. In the past decades, the hog market weight has increased worldwide. However, whether the genetic architecture of feeding efficiency is same or not at early and late fattening periods is unclear. To map genomic regions for feed efficiency and feeding behavior traits at early (n ≥ 384) and late (n ≥ 334) growth stages in pigs, we performed genomewide association studies for feed to gain ratio (FCR), residual feed intake (RFI), daily feed intake, daily visit times, daily feeding time (DFT), feed intake per second (FIPS), and feed intake per visit during 3 periods (2 stages and overall) in a White Duroc × Erhualian F2 intercross population. Six chromosomal regions showed significant association with these traits, of which 4 loci were reported for the first time. Our results confirmed the QTL of FCR around 34 Mb on SSC7 and RFI around 134 Mb on SSC12. Of note, 2 regions were associated with more than 1 trait. One was around 36 Mb on SSC7, and there were 47 and 67 SNP associated with FCR from 120 to 210 and from 120 to 240 d, respectively. The top SNP is located in a 2.88-Mb linkage disequilibrium (LD) block that harbors 44 genes. We propose the high mobility group AT-hook 1 gene as a plausible candidate gene in this region. The other was evidenced around 53 Mb on SSC12, which had multiple association signals for DFT and FIPS. The top SNP is located in a 211-kb LD block that harbors only 1 annotated gene, WSCD1, which encodes a protein with sulfotransferase activity and involves the glucose metabolism and, therefore, appears to be a plausible candidate gene. Except the region on SSC12 associated with DFT at both stages, the rest of the regions associated with the traits at only 1 stage, so the genetic architectures of the 2 stages are not same.

Gestation length and maternal ability are important to improve the sow reproduction efficiency and their offspring survival. To map quantitative trait loci (QTL) for gestation length and maternal ability related traits including piglet survival rate and average body weight of piglets at weaning, more than 200 F 2 sows from a White Duroc 3 Erhualian resource population were phenotyped. A genome-wide scan was performed with 194 microsatellite markers covering the whole pig genome. QTL analysis was carried out using a composite regression interval mapping method via QTL express. The results showed that total number of born piglets was significantly correlated with gestation length (r 5 20.13, P , 0.05). Three QTL were detected on pig chromosome (SSC)2, 8 and 12 for gestation length. The QTL on SSC2 achieved the 5% genome-wide significant level and the QTL on SSC8 was consistent with previous reports. Four suggestive QTL were identified for maternal ability related traits including 1 QTL for survival rate of piglets at weaning on SSC8, 3 QTL for average body weight of piglet at weaning on SSC3, 11 and 13.

To identify QTL for feed consumption and feeding behavior traits in pigs, ADFI, feed conversion ratio (FCR), number of visits to the feeder per day (NVD), and average feeding rate (AFR) were recorded in 577 F(2) animals from a White Duroc x Chinese Erhualian resource population during the fattening period of 120 to 240 d. A whole genome scan was performed with 183 microsatellites covering the pig genome across the entire resource population. A total of 8 QTL were identified on 5 pig chromosomes, including 3 genome-wide significant QTL for FCR on SSC2, 7, and 9, 1 significant QTL for ADFI on SSC3, and 1 for NVD on SSC7. These QTL were identified for the first time, except for the QTL for FCR on SSC2. Four of the 5 significant QTL were adjacent to the known QTL for growth, carcass, and fat deposition traits, supporting the existence of gene(s) with pleiotropic effects on these traits. White Duroc alleles were generally associated with greater phenotypic values, except for those on SSC7 and 9. Comparison of QTL for feed consumption and feeding behaviors indicated that distinct chromosomes had effects on the 2 types of traits. Characterization of causative gene(s) underlying the identified QTL would shed new light on the genetic basis of feed consumption and feeding behaviors in pigs.

China harbors a very rich plant biodiversity both in total number of taxa and in endemism. Nevertheless, a signifi cant fraction of this diversity (up to 20% of the native plants to China) is currently threatened. Among this endangered fl ora, an appreciable but still unquantifi ed number of taxa are in an extreme situation of risk because of their low population sizes, often consisting of fewer than 100 individuals. We have selected 20 plant taxa as a sample of this extremely threatened fl ora, and, from these, information about their geographic range, population size, threats, existing conservation measures, legal status and threat degree (according to the IUCN criteria) is provided. The extreme rarity of these taxa can be linked to their evolutionary history (they are palaeo-or neoendemics) and/or to severe human disturbance (mostly habitat destruction and overexploitation) affecting them.