number of embryos transferred). Of those 34 embryos, only 8 individual pregnancies resulted (Column 5). Of those 8 pregnancies, 3, or 38%, ended in miscarriage, and 5, or 63%, went on to produce live offspring (Columns 6 and 7, respectively). Of the five lambs that were born alive, only 2 (40%) survived until the time of publication. In all, 2% of the 244 embryos created resulted in live offspring (Column 9), and 12.5% of the 34 embryos transferred into recipient female sheep resulted in live offspring (Column 8).

How to read Table 2:

Any given line in Table 2 gives an overview of the clinical outcomes of each animal reproductive cloning experiment. For example, in line 1, in the sheep nuclear transplantation experiments published by Campbell in 1996 (Column 7), no information was given concerning the defects seen in miscarried fetuses (Column 3) or about the characteristics of placentas from these pregnancies (Column 6). However, Columns 4 and 5 indicate that 2/5 of the cloned lambs produced in this experiment were healthy and normal, whereas 3/5 died of unknown causes.

Note about Figures 1, 2, and 3

Figures 1, 2, and 3 were generated based on data presented in Table 1. Certain experiments whose results are displayed in Table 1 were omitted from the graphs due to incomplete data for all categories displayed in the graphs. Data from reproductive cloning experiments using embryonic, fetal and adult cells as nucleus donors were included in these graphs.

The National Academies of Sciences, Engineering, and Medicine
500 Fifth St. N.W. | Washington, D.C. 20001

Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement