RT Journal Article SR Electronic T1 Another human chimaera JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 283 OP 287 DO 10.1136/jmg.11.3.283 VO 11 IS 3 A1 Battey, Diana A. A1 Bird, G. W. G. A1 McDermott, A. A1 Mortimer, C. W. A1 Mutchinick, O. M. A1 Wingham, June YR 1974 UL http://jmg.bmj.com/content/11/3/283.abstract AB Another human chimaera is described, which we are unable to classify because of limited family data. Evidence of chimaerism was confined to haemopoietic tissues. There were two red cell populations with differences in four blood group systems and, although the patient was female, chromosome analysis of cultured lymphocytes showed that 96% of cells had the male karyotype 46,XY. Possible mechanisms for the production of chimaeras are discussed.