en Biotechnology Biotechnology پژوهشي Orginal research papers <span style="font-size:11pt"><span style="line-height:120%"><span style="font-family:Calibri,sans-serif"><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times=""><span style="color:black">Genus <i>Ulva</i> includes edible seaweed species with extensive morphological overlaps, plasticity, and intra specific variation, making it taxonomically difficult to classify. <i>Ulva </i>species occur in the Persian Gulf, and Oman Sea, but there is no detailed information on their genetic structure, diversity, as well as species relationships. Aims of the present study were to: (1) identify existing species of the genus <i>Ulva </i>in selected areas of the Persian Gulf and Oman Sea, and (2) illustrate species relationships by a combination of morpho-anatomical and molecular data. Based on morphological features, 10 <i>Ulva </i>species were identified which were confirmed by their DNA homology with the reported taxa. The <i>Ulva </i>species were delineated using a combination of morphological, anatomical and molecular data (ISSR, SCoT, ITS, <i>rbc</i>L<i>,</i> and <i>tufA</i> region sequences). AMOVA revealed species genetic differentiation and a higher level of intra-specific diversity in <i>Ulva</i>. The species relationship is discussed based on genetic and morphological data. A kind of divergent selection on morphological characters and in response to geographical coordinates is suggest</span></span></span></span><span style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times=""><span style="color:black">ed.</span></span></span></span></span></span></span> AMOVA, Genetic diversity, Persian Gulf, Oman Sea, Ulva 1017 1046 http://jifro.ir/browse.php?a_code=A-10-4210-1&slc_lang=en&sid=1 N. Farasat nasrinfarasat48@yahoo.com n_farasat@sbu.ac.ir 100319475328460047697 100319475328460047697 No Shahid Beheshti University, Tehran, Iran M. Sheidai msheidai@sbu.ac.ir 100319475328460047698 100319475328460047698 Yes Shahid Beheshti University, Tehran, Iran H. Riahi h-riahi@sbu.ac.ir 100319475328460047699 100319475328460047699 No Shahid Beheshti University, Tehran, Iran F. Koohdar f_koohdar@yahoo.com 100319475328460047700 100319475328460047700 No Shahid Beheshti University, Tehran, Iran M. Farasat mehfarasat@gmail.com 100319475328460047701 100319475328460047701 No Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran