Lack of detection of a putative retrovirus associated with haemic neoplasia in the soft shell clam Mya arenaria

► Whole tissues of both HN+ve and HN−ve animals were exposed to sucrose gradient. ► The fractions with highest RT activity were exposed to RNA, protein, and EM analysis. ► There was no evidence for existing of a putative retrovirus. ► RT-PCR using universal primers of retroviruses was negative in all tested samples.