Germ Line Colonization of Cells, Level of Chimerism and Sex Ratio in Chimeric Mice

Authors: Sezen ARAT

Abstract: The aims of this study were to determine the degree of chimerism, germ line colonization of cells from two different mouse strains and the sex ratio in the chimeric mice. The aggregation technique was used to produce the chimeras. Pairs of embryos, ona from C57BL/6 strain the other from BALB/C strain were cultured for 24 hours. 72% of the embryo pairs aggregated and developed to chimeric morulae and blastocysts. 65% of aggregates which were transferred to the recipient developed to term. 37% of offsprings were chimeric (22 offsprings). 15 out of 22 chimeric offsprings were phenotypic male and 7 were phenotypic female. The level of chimerism was iidentified by coat colour examination of chimeras. In most of the chimeras, albino colour was dominant and when chimeras were mated with BALB/C strain mice, most of their offsprings were albino. This study showed that the cells derived from C57BL/6 embryos colonized all tissues, including the germ line in lower rates than the cells from BALB/C embryos.

Keywords: Mouse, chimera, sex ratio