Porcine (Sus scrofa domestica) chromosome identification and suggested nomenclature

Various banding techniques have been used for chromosome analysis in domestic pigs (Sus scrofa domestica). The techniques used in karyotype analysis were Q-banding by (CMA)2S, trypsin-G-banding, BrdU-Acridine-Orange R-Banding and C-banding. Sequential staining techniques of quinacrine-Giemsa were used to record the length of each chromosome and determine arm ratios. Sequential Quinacrine-Giemsa-Ag-AS treatment was used to locate the nucleolar organizer (NOR) on specific chromosomes. A G-C specific fluorochrome was used for reverse fluorescent banding and to differentiate certain chromosome regions which may contain G + C rich DNA. Unequivocal identification of all individual autosomes and sex-chromosomes in the porcine complement is now possible. The X-chromosome of the species has a banding pattern similar to the human X-chromosome. A nomenclature system similar to that used for human chromosomes is proposed for the G-banded and Q-banded karyotype of the domestic pig. The results of C-banding and olivomycin fluorescent banding suggest that at least three types of heterochromatin are contained in the porcine genome.