Data from: Rapid divergence of mussel populations despite incomplete barriers to dispersal

Striking genetic structure among marine populations at small spatial scales is becoming evident with extensive molecular studies. Such observations suggest isolation at small scales may play an important role in forming patterns of genetic diversity within species. Isolation-by-distance, isolation-by-environment, and historical priority effects are umbrella terms for a suite of processes that underlie genetic structure, but their relative importance at different spatial and temporal scales remains elusive. Here, we use marine lakes in Indonesia to assess genetic structure and test relative roles of the processes in shaping genetic differentiation in populations of a bivalve mussel (Brachidontes sp.). Marine lakes are landlocked water bodies of similar age (6,000 – 10,000 years), but with heterogeneous environments and varying degrees of connection to the sea. Using a population genomic approach (double-digest Restriction-site Associated DNA sequencing), we show strong genetic structuring across populations (range FST: 0.07 – 0.24), and find limited gene flow through admixture plots. At large spatial scales (>1400km), a clear isolation-by-distance pattern was detected. At smaller spatial scales (<200km), this pattern is maintained, but accompanied by an association of genetic divergence with degree of connection. No signatures of isolation-by-environment were found. We hypothesize that (incomplete) dispersal barriers can cause initial isolation, allowing priority effects to give the numerical advantage necessary to initiate strong genetic structure. Priority effects may be strengthened by local adaptation, which our data potentially corroborates by showing a high correlation between mussel genotypes and temperature. Our study indicates an often-neglected role of evolution-mediated priority effects in shaping divergence

Rapid divergence of mussel populations despite incomplete barriers to dispersal

Striking genetic structure among marine populations at small spatial scales is becoming evident with extensive molecular studies. Such observations suggest isolation at small scales may play an important role in forming patterns of genetic diversity within species. Isolation‐by‐distance, isolation‐by‐environment, and historical priority effects are umbrella terms for a suite of processes that underlie genetic structure, but their relative importance at different spatial and temporal scales remains elusive. Here, we use marine lakes in Indonesia to assess genetic structure and test relative roles of the processes in shaping genetic differentiation in populations of a bivalve mussel (Brachidontes sp.). Marine lakes are landlocked water bodies of similar age (6,000 – 10,000 years), but with heterogeneous environments and varying degrees of connection to the sea. Using a population genomic approach (double‐digest Restriction‐site Associated DNA sequencing), we show strong genetic structuring across populations (range FST: 0.07 – 0.24), and find limited gene flow through admixture plots. At large spatial scales (>1400km), a clear isolation‐by‐distance pattern was detected. At smaller spatial scales (<200km), this pattern is maintained, but accompanied by an association of genetic divergence with degree of connection. No signatures of isolation‐by‐environment were found. We hypothesize that (incomplete) dispersal barriers can cause initial isolation, allowing priority effects to give the numerical advantage necessary to initiate strong genetic structure. Priority effects may be strengthened by local adaptation, which our data potentially corroborates by showing a high correlation between mussel genotypes and temperature. Our study indicates an often‐neglected role of evolution‐mediated priority effects in shaping population divergence

DNA barcoding and morphometric of Rastrelliger Spp in North Maluku Sea. Indonesia

High exploration activity is feared to have an impact to mackerel populations. A sustainable management approach should be taken to provide information about the status of mackerel populations. Study of mackerel population status can be carried out through genetic information. The DNA of the fish samples were collected at traditional fish markets (Ternate, Morotai and Bacan, South Halmahera District). Laboratory works such as extraction, amplification, electrophoresis and DNA sequencing were analysis at the Indonesian Biodiversity Laboratory (BIONESIA). The molecular characteristics of Rastrelliger kanagurta were 374 base pairs (bp). The composition of nucleotides showed the similarity of frequencies between species. Phylogenetic relationship of R. kanagurta in North Maluku Sea suggested that there was any differentiation. The genetic diversity of R. kanagurta was high with a total number of haplotypes and diverse nucleotide diversity. The minimum spawning networks (MSN) found 5 haplotype networks from a total of 12 samples. Morphological measurements of standard length, head height, body width, pectoral fin length and tail were found to have variable values. The length of the weight of the fish is obtained of b = 3, indicating that the growth pattern was isometric or weight gain was equivalent to the growth of the fish length.Keywords : biodiversity, conservation, ecology, morphology, specie