Mitochondrial genome of the Peruvian scallop Argopecten purpuratus (Bivalvia: Pectinidae).

The mitochondrial genome of the Peruvian scallop Argopecten purpuratus was determined. The length of the mitochondrial coding region is 15,608 bp. A typical bivalve mitochondrial composition was detected with 12 protein-coding genes, 2 ribosomal RNA genes and 21 transfer RNA genes, with the absence of the atp8 gene. Fifty percent of the protein-coding genes use typical ATG start codon, whereas five genes utilize ATA as their start codon. Only one gene was found to utilize TTG as its start codon. The A. purpuratus mitogenome shows a significant similarity to that of A. irradians irradians, in length as well as in gene composition.

Disruption of normal meiosis in artificial inter-populational hybrid females of Misgurnus loach.

Artificial cross between two genetically different populations of Japanese Misgurnus loach was made to examine the reproductive capacity of the artificial inter-populational hybrid females. Ploidy status and microsatellite genotypes of the eggs laid by these hybrids were inferred from those determined in progenies developed by normal fertilization with haploid loach sperm, induced gynogenesis with UV-irradiated goldfish sperm and/or hybridization with intact goldfish sperm. Some hybrid females laid unreduced diploid eggs genetically identical to the mother. However, these diploid eggs could not develop by spontaneous gynogenesis, but grow to triploid by incorporation of a sperm nucleus. Other hybrid females laid haploid eggs together with diploid eggs and/or various aneuploid and polyploid eggs. Thus, a disruption of normal meiosis occurred in inter-populational hybrid females. The results suggested that the two populations should be so distant as to give rise to atypical formation of unreduced and other unusual eggs in their hybrids.