Genetic differentiation and distribution of Pyropia acanthophora (Bangiales,Rhodophyta) in the Philippines

Pyropia acanthophora is a foliose Bangiales with widely known endemic populations in Indo-Pacific region. This alga has expanded its range recently as a consequence of introduction. In an attempt to explore the genetic diversity of Py. acanthophora within the Philippines and the impact of the introduction of the species from elsewhere, an examination of molecular differentiation and distribution was undertaken using the mitochondrial COI-5P and plastid rbcL gene sequences. The results revealed that the populations of Py. acanthophora in the Philippines exhibited high haplotypic and genetic diversities, and were found to be distinct from those previously reported as conspecific populations found in Taiwan, India, Japan, Hawaii, and from those introduced populations from Brazil. The network analyses as inferred from rbcL and from the combined COI-5P and rbcL genes showed evidence that the Philippine populations of Py. acanthophora exhibited a chaotic patchiness pattern characterized by a population with highly site-exclusive haplotypes, wide genetic variability and lack of local geographic patterns. The distribution of Py. acanthophora within the Philippines was also found to be greater than what was previously known, ranging from the extreme northwest to extreme northeast mainland Luzon coasts, including Camiguin Is., Cagayan. Understanding the genetic diversity and distribution of Py. acanthophora in the Philippines provides valuable information in relation to the conservation and effective resource management of native populations of Py. acanthophora in the tropical Asian region.