Lymphoid hypoplasia and somatic cloning

Background Adult somatic cloning by nuclear transfer is associated with hig h rate of perinatal mortality but there is still no evidence that nuclear t ransfer itself is responsible for these failures. We report on a longlastin g defect linked to somatic cloning. Methods Skin cells grown from an ear biopsy specimen from a 15-day-old calf were used as a source of nuclei. The donor animal was a clone of three fem ales obtained from embryonic cells. Clinical examination, haematological, a nd biochemical profiles, and echocardiography of the somatic clone were don e from birth to death. Findings After 6 weeks of normal development, the somatic cloned calf had a sudden and rapid fall in lymphocyte count and a decrease in haemoglobin. T he calf died on day 51 from severe anaemia. Necropsy revealed no abnormalit y except thymic atrophy and lymphoid hypoplasia. Interpretation Somatic cloning may be the cause of longlasting deleterious effects. Our observation should be taken into account in debates on reprodu ctive cloning in human beings.