Incidental production of tetraploid Manila clams, Tapes philippinarum (Adams and Reeve)

Standish K. Allen, Muki Shpigel, Susan Utting, Brian Spencer

Research output: Contribution to journalArticlepeer-review


For about 10 years the quest for tetraploid bivalves has eluded researchers leading to doubts that tetraploids were viable. Recently two reports of tetraploid shellfish have led to increased optimism. We document a third species in which tetraploids are viable. Newly fertilized eggs of the Manila clam, tapes philippinarum (Adams and Reeve), were treated with cytochalasin B from 20-40 min post-fertilization to induce triploidy. Following standard nursery culture, juveniles were planted at two locations for analysis of growth differences between diploid and triploid clams. Samples from the planted populations were taken at regular intervals from March, 1993. Of 200 clams sampled from the Welsh site, 1 was unequivocally tetraploid; of 120 clams sampled in Israel, 2 were tetraploid, and 2 were hypotetraploid. Tetraploids formed gametes with eggs about 41% larger than diploids. Tetraploids were produced as an artifact of triploid induction, either from inhibition of the first polar body alone or in combination with the second, or by inhibition of the first mitotic division. Production of artifact groups like tetraploids suggests that development of the eggs was asynchronous. The major implication of these findings is that tetraploidy can be tolerated in T. philippinarum and apparently at least two other species, and some evidence exists for gamete production, therefore offering encouragement for continuing research on induced tetraploidy in shellfish.

Original languageEnglish
Pages (from-to)13-19
Number of pages7
Issue number1-2
StatePublished - 1 Dec 1994
Externally publishedYes


  • Genetics
  • Polyploidy
  • Tapes philippinarum
  • Tetraplaidy

ASJC Scopus subject areas

  • Aquatic Science


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