Progeny of Somatic Cell Nuclear Transfer (SCNT) Pig Clones Are Phenotypically Similar to Non-Cloned Pigs

Abstract

Systematic studies of cloned animals generated from adult somatic cell nuclei are critical in assessing the utility of somatic cell cloning in various applications, including the safety of food products from cloned animals and their offspring. Previously, we compared somatic cell derived cloned pigs with naturally bred control pigs on a series of physiological and genetic parameters. We have extended our studies to the F1 progeny of these clones to see whether these phenotypic differences are transmitted to the next generation. There were no differences in the average litter size between litters from cloned gilts and naturally bred controls (7.78 +/- 2.6 and 7.40 +/- 3.0, respectively; mean +/- SD) or in the degree of litter size variation (coefficients of variation of 33.4% and 40.5% for litters of clones and controls, respectively). Similarly there were no statistical differences between sex ratios of cloned litters (51-49%, M:F) and control litters (59-41%, M:F). Blood profiles between cloned pigs, control pigs, and their progeny were compared at two time points (i.e., 15 and 27 weeks) to quantify the effect of cloning on various blood parameters and their transmission to the next generation. Although the range of values for all traits overlapped between different classes, the variability between all the traits in F1 progeny of clones and the control pigs was similar at 15 and 27 weeks, with one exception. Combined, our data and previous results in mice strongly support the hypothesis that offspring of clones are similar to offspring of naturally bred animals, and as such there should not be any increased risks associated with consumption of products from these animals.

Comparison of the Growth Performances of Offspring Produced by a Pair of Cloned Cattle and Their Nuclear Donor Animals

“…When the results of routine serum biochemistry and hematology of the Japanese Black breed calf produced here were compared with those of its herd mate, no abnormal values were found in either animal. Similarly, analysis of piglets produced by mating pairs of cloned pigs did not reveal any abnormal values in the serum biochemistry results for creatinine, alkaline phosphatase, blood urinary nitrogen, albumin, phosphatase, calcium, serum protein, or glucose [13]. These results appear to support the hypothesis that the progeny of pairs of clones are similar to those of naturally bred animals.…”

“…To quantify the risk, it is clearly essential to study the offspring produced by cloned dams and sires. To date, however, the available information is limited to two studies, one in cattle [12] and the other in pigs [13].…”

Treatment with a Histone Deacetylase Inhibitor after Nuclear Transfer Improves the Preimplantation Development of Cloned Bovine Embryos

“…It has been reported that, in SCNT, embryo losses occur at various stages, and the anomalies in fetal and perinatal stages have been observed [1][2][3][4][5][6]. Because such abnormalities of clones are not transmitted to their progenies [7][8][9][10][11][12], most of the developmental problems of clones are believed to be the results of epigenetic defects [13]. In fact, several studies have revealed abnormal epigenetic modifications such as DNA methylation and histone modifications in SCNT embryos [14][15][16][17].…”

The ecological adaptability of cloned sheep to free-grazing in the Tengger Desert of Inner Mongolia, China

“…In pigs, Shibata et al [4] and Hu et al [5] reported that cloned pigs and their offspring were similar to others of the same breed in growth, reproduction and meat production [6]. The reproductive characteristics of cloned boars are highly comparable to naturally produced boars [7,8].…”