Occurrence of two different reciprocal translocations in the same litter of domestic pigs

Abstract

A translocation designated t(9p+;l Iq-) was found in a boar producing small litters but having a normal sexual behaviour and a normal semen picture. Investigation of one of his litters revealed, in addition to t(9p+;l lq-) in two individuals, another translocation designated rcp(lp-;Xq+) in all offspring. The latter translocation had been transmitted from the dam. Both translocations concerned greatly unequalsized chromosome segments but only rcp( lp-;8q+) could be demonstrated to be truly reciprocal. The breakages of both translocations had occurred in RBA-positive bands of telomeric and centromeric segments. These observations support the hypothesis that aberrations occur non-randomly in chromosomes and chromosome segments of the pig karyotype. Embryonic studies indicated that probably only one chromosomally unbalanced gametic product, dexfl l)t(9p+; 1 lq-), can survive implantation. The t(9p +; I Iq -) effected a reduced litter size of approximately 50 % in the proband and it was also assumed, although evidence was lacking, that rcp( lp-;8q+) implied impaired fertility for the carriers. Newborns had either normal or balanced heterozygous karyotype. Those boars demonstrated a normal sexual behaviour and a normal semen picture. The finding of translocations almost exclusively in the male sex is probably attributable to the fact that boars are more often used for extensive breeding work than are females, and fertility impairment is therefore more easily detected in the male sex.A boar with normal sexual behaviour and normal semen picture, yet producing small litters, demonstrated a chromosomal translocation designated t(9p+;Ilq-). When a litter sired by this boar was studied in order to obtain information about the heredity of t h e translocation, an additional translocation, rcp( Ip -;8q+) was found. 1964; LOCNISKARet al. 1976; HAGELTORNet Ell. 1976; The latter translocation had been transmitted from the dam. The present work describes the cytogenetic and hereditary features of the two translocations, their behaviour in male meiosis and their role in embryonic mortality and fertility. Materials and methodsThe pigs investigated were of the Swedish Yorkshire breed. The proband and his progeny available at the farm were studied, and so were the available dams of those litters. Two whole-brothers available at neighbouring farms were also studied. Blood samples were taken from a total of 8 adult animals and skin biopsies from 30 piglets. Embryos were recovered, measured and morphologically examined, from two gilts and one sow 21 days after mating with the proband.Cultures were set up in conventional ways. The lymphocytes were grown in medium RPMI 1640 plus 30 % foetal calf serum and stimulated with pokeweed (Grand Island). The skin biopsies and embryos were cut into small pieces, explanted in

A reciprocal translocation (7q-;12q+) in the domestic pig

“…Two litters from the same boar were also studied, one with 7 piglets (4 females and 3 males) and the other with 6 (6 females).Blood samples for chromosome analysis were collected from the ear vein of the boar and from the vena cava cranialis of the piglets. Blood lymphocytes were cultured according to the method of GUSTAVSSON et al (1983). Lung tissue for fibroblast cultures was collected from the boar at slaughter and processed according to the standard method.The chromosomes were stained by GTG (SEA-BRIGHT 1971), RBA (DUTRILLAUX et al 1983) and CBG (SUMNER 1972) methods.…”

“…Blood samples for chromosome analysis were collected from the ear vein of the boar and from the vena cava cranialis of the piglets. Blood lymphocytes were cultured according to the method of GUSTAVSSON et al (1983). Lung tissue for fibroblast cultures was collected from the boar at slaughter and processed according to the standard method.…”