Local adaptations can determine the potential of populations to respond to environmental changes, yet adaptive genetic variation is commonly ignored in models forecasting species vulnerability and biogeographical shifts under future climate change. Here we integrate genomic and ecological modeling approaches to identify genetic adaptations associated with climate in two cryptic forest bats. We then incorporate this information directly into forecasts of range changes under future climate change and assessment of population persistence through the spread of climate-adaptive genetic variation (evolutionary rescue potential). Considering climate-adaptive potential reduced range loss projections, suggesting that failure to account for intraspecific variability can result in overestimation of future losses. On the other hand, range overlap between species was projected to increase, indicating that interspecific competition is likely to play an important role in limiting species’ future ranges. We show that although evolutionary rescue is possible, it depends on a population’s adaptive capacity and connectivity. Hence, we stress the importance of incorporating genomic data and landscape connectivity in climate change vulnerability assessments and conservation management.
MicroRNAs (miRNAs) are important post-transcriptional gene expression regulators. Here, 448 different miRNA genes, including 17 novel miRNAs, encoding for 589 mature Atlantic salmon miRNAs were identified after sequencing 111 samples (fry, pathogen challenged fry, various developmental and adult tissues). This increased the reference miRNAome with almost one hundred genes. Prior to isomiR characterization (mature miRNA variants), the proportion of erroneous sequence variants (ESVs) arising in the analysis pipeline was assessed. The ESVs were biased towards 5’ and 3’ end of reads in unexpectedly high proportions indicating that measurements of ESVs rather than Phred score should be used to avoid misinterpreting ESVs as isomiRs. Forty-three isomiRs were subsequently discovered. The biological effect of the isomiRs measured as increases in target diversity was small (<3%). Five miRNA genes showed allelic variation that had a large impact on target gene diversity if present in the seed. Twenty-one miRNAs were ubiquitously expressed while 31 miRNAs showed predominant expression in one or few tissues, indicating housekeeping or tissue specific functions, respectively. The miR-10 family, known to target Hox genes, were highly expressed in the developmental stages. The proportion of miR-430 family members, participating in maternal RNA clearance, was high at the earliest developmental stage.
Minisatellite-based DNA profiling was used to investigate the dispersion of synchronously spawned families of Atlantic salmon (Salmo salar L.) fry from artificial nests in a natural stream. By the end of the summer, i.e., 17 weeks after hatching, detected dispersion was mainly downstream and less than 1 km. Within this distance, three families that had been stocked together showed different patterns of dispersion, with the relative abundance of each family changing systematically with distance downstream from the nest, but with no monopolization of any area or habitat type by any one family. The length of fry also changed systematically with distance downstream, with the patterns of change depending on family. For each family, fry were larger closer to the nest. Changes in habitat type had a common effect on the density and length of fry from all the families.
Summary. Molecular variants of the serotype-specific plasmid (SSP) of Salmonella typhimurium (pSLT) were recognised in clinical and veterinary isolates by restriction enzyme fingerprinting. Three had undergone minor DNA rearrangements, whereas two had acquired resistance determinants to a wide range of antimicrobial agents including gentamicin, trimethoprim, tetracycline, streptomycin, ampicillin (Ap) and kanamyciii (Km). One of the latter was the result of co-integrate formation with an IncX, conjugative R-plasmid that specified ApKm resistance. The co-integrate plasmid (pOG669) was incompatible with, and displaced, pSLT and its molecular variants. The restriction fingerprints of SSPs of S. enteritidis and S . dublin were compared with pSLT. All were related at the 35% level on the basis of a Dice coefficient of similarity. The SSPs of S. enteritidis and S . dublin were incompatible with the co-integrate plasmid pOG669. Whereas in S. enteritidis this resulted from incompatibility with the pSLT component (the SSP was compatible with the IncX component), the converse was found with S. dublin.
Background: Tilapias (Family Cichlidae) are the second most important group of aquaculture species in the world. They have been the subject of much research on sex determination due to problems caused by early maturation in culture and their complex sex-determining systems. Different sex-determining loci (linkage group 1, 20 and 23) have been detected in various tilapia stocks. The 'genetically improved farmed tilapia' (GIFT) stock, founded from multiple Nile tilapia (Oreochromis niloticus) populations, with some likely to have been introgressed with O. mossambicus, is a key resource for tilapia aquaculture. The sex-determining mechanism in the GIFT stock was unknown, but potentially complicated due to its multiple origins. Results: A bulk segregant analysis (BSA) version of double-digest restriction-site associated DNA sequencing (BSA-ddRADseq) was developed and used to detect and position sex-linked single nucleotide polymorphism (SNP) markers in 19 families from the GIFT strain breeding nucleus and two Stirling families as controls (a single XY locus had been previously mapped to LG1 in the latter). About 1500 SNPs per family were detected across the genome. Phenotypic sex in Stirling families showed strong association with LG1, whereas only SNPs located in LG23 showed clear association with sex in the majority of the GIFT families. No other genomic regions linked to sex determination were apparent. This region was validated using a series of LG23-specific DNA markers (five SNPs with highest association to sex from this study, the LG23 sex-associated microsatellite UNH898 and ARO172, and the recently isolated amhy marker for individual fish (n = 284). Conclusions: Perhaps surprisingly given its multiple origins, sex determination in the GIFT strain breeding nucleus was associated only with a locus in LG23. BSA-ddRADseq allowed cost-effective analysis of multiple families, strengthening this conclusion. This technique has potential to be applied to other complex traits. The sex-linked SNP markers identified will be useful for potential marker-assisted selection (MAS) to control sex-ratio in GIFT tilapia to suppress unwanted reproduction during growout.
Levels of variation at six VNTR (variable number of tandem repeats) loci, one minisatellite and five microsatellite loci, isolated from tri-and tetranucleotide enriched DNA libraries for northern pike were generally low in two Danish populations (1-4 alleles; expected heterozygosity 0-0·57), though one highly variable microsatellite (13 alleles; expected heterozygosity 0·79) was identified. In combination with previously published microsatellites a set consisting of nine polymorphic loci appeared to be useful for discriminating populations, as determined by assignment tests. 1999 The Fisheries Society of the British Isles
SUMMARYRestriction enzyme fingerprints were generated from purified plasmid DNA from 324 clinical isolates that belonged to 7 enterobacterial genera and 88 single plasmids in Escherichia coli K 12 according to the following strategy.Purified plasmid DNA was digested with PstI. The number of fragments detected in a 0-8 agarose gel was used to determine which 2 of 6 restriction enzymes including PstI was most likely to provide a fingerprint comprising sufficient fragments to ensure specificity but sufficiently few to allow easy visual assessment and minimize coincidental matching. When Pst I produced > 20 fragments, Eco RI and Hind III were used; when PstI generated < 6 fragments Bsp 1286 and AvaII were used and SmaI was employed when between 6 and 20 fragments were obtained from PstI digests. Using a minimum of 12 fragments from a combination of 2 enzymes as the criterion for characterizing a strain/plasmid, satisfactory 2-enzyme fingerprints were obtained from 87 % of the strains and plasmids studied using Pst I and no more than two additional enzymes per strain. Of the remaining 54 strains, 51 harboured only small plasmids (< 10 kb) and 3 produced satisfactory fingerprints when digested with a fourth enzyme.
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