TABLE 2

Developmental competence of intergeneric NT embryos reconstructed using ovine oocytes with mtDNA+ and mtDNAR SFF2 donor cells

Donor cellsReplicatesFused couplets (%)Cleavage2-cells (%)>4–12 cells(%)>16 cells(%)Morula and blastocyst (%)
mtDNA+395/116 (81.9) (a)52/95 (54.7) (a)28/41 (68.3) (a)6/41 (14.6) (a)0
mtDNAR3111/119 (93.3) (b)76/111 (68.4) (a)57/76 (74) (a)24/51 (47) (b)0
  • In each case, the numbers of embryos that reached a particular stage of development are expressed as a fraction of the total number of embryos available to develop to that stage with percentage values stated in parentheses. The variability in numbers for each stage of development is due to a proportion of embryos being harvested at each stage of development for analysis. mtDNA+ donor cells were cultured to the same time point as mtDNAR cells. Significance is denoted by letters (a and b) where the two letters for a particular developmental stage differ, as determined using a Fisher's exact test. Where both letters are “a”, significance was not found (P > 0.0125 after Bonferroni correction for multiple comparisons). The number of fused couplets was significantly different between the two embryo cohorts (P = 0.01). There were no significant differences between groups of embryos that cleaved or those at the 4–12-cell stages (P > 0.0125). A significantly greater number of embryos developed to the >16-cell stage for mtDNAR than for mtDNA+ (P < 0.002). No embryos reached the morula or blastocyst stage of development.