Royana: Successful Experience In Cloning The Sheep

Document Type : Original Article


1 Stem Cells Department, Cell Sciences Research Center, Royan Institute, ACECR, Tehran, Iran

2 Clinical and Experimental Embryology Department, Cell Sciences Research Centre, Royan Institute, ACECR, Isfahan, Iran

3 Department of Clinical and Experimental Embryology, Reproductive Medicine Research Centre, Royan Institute, ACECR, Tehran, Iran

4 Isfahan Fertility and Infertility Center, Isfahan, Iran

5 Faculty of Basic Science, Islamic Azad University, Marvdasht Branch, Iran

6 Anatomy Department, School of Medical Sciences, Tarbiat Modarres University, Tehran, Iran

7 Genetic Department, Reproductive Medicine Research Centre, Royan Institute, ACECR, Tehran, Iran

8 Clinical Sciences Department, Faculty of Veterinary, Tehran University, Tehran, Iran

9 Obstetric and Gynecology Unit, Fooka Dairy Complex, Social Security Association, Isfahan, Iran


Objective: This study describes our experiences in reproductive cloning using two different procedures resulting in birth of the first successfully cloned sheep in Iran and the 
Middle-East, nick-named "Royana".
Materials and Methods: Abattoir-derived sheep oocytes were enucleated after in vitro 
maturation for 18-20hrs and then reconstructed by ear-derived sheep somatic cells using 
two different procedures of renucleation (subzonary, intracytoplasmic), embryo culture (coculture, sequential medium) and embryo transfer (intra fallopian, intra uterine). Pregnancy 
status and fetal development were followed regularly and elective cesarean was inducted 
on day 145 of pregnancy. Histopathological and genetical examinations were performed 
on either aborted and delivered clones for confirmation different aspects of cloning.
Results: The two procedures were both efficient in producing early and/or advanced 
cloned embryos, establishing early and/or advanced stages of pregnancy till delivery. Four 
pregnancies were detected; one were failed at early pregnancy, one aborted on day 90, 
one was still born and the fourth delivered to a healthy male lamb nick named "Royana".
Conclusion: Many different approaches have been developed for mammalian cloning 
which all are judged by their ultimate potency for establishment of successful pregnancies terminated to healthy/viable clones. As a preliminary study toward establishment of 
the technology, this study also successfully examined the competency of two procedures 
of somatic cell nuclear transfer (SCNT). However, the overall low efficiency of SCNT indicates that many different aspects of the technology remain to be dissolved.