Northern quahogs (=hard clam; Mercenaria mercenaria) is a commercially important bivalve naturally distributed along the American Atlantic coast. Because the hard clam was first introduced into China as a candidate for aquaculture in 1997, research has been conducted on its ecologic habits, ecological physiology, metabolism, growth, reproduction, artificial propagation, and seed culture. Little information about their chromosomes and karyotype is available. The present study is designed to study the karyotype of the diploids and triploids to provide a reference to genetic research on introduced M. mercenaria. Triploids were produced by inhibiting the release of second polar body (PBII) with a treatment of 450 μmol/mL 6-deimethylaminopurine (6-DMAP), with untreated fertilized eggs developing as normal diploid controls. Chromosome preparations were made from trochophore larvae with drop-splash method. Chromosomes were measured and classified according to Leven criteria. Statistical analysis of relative length and arm ratio revealed that, this species had a normal diploid chromosome number of 2n = 38, and the karyotype consists of 15 pairs of metacentric (M) and 4 pairs of submetacentric (SM) chromosomes, NF = 76. The triploid karyotype formula was 45 M 12 SM, NF = 114. The heterochromosomes and satellite chromosomes were not observed in all chromosomes in the complement.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 27 • No. 2