Abstract
We confirmed chimeric heterosis for body weight in chimeric mice and examined the relationship between heterosis and the relative proportions of two cell populations in their bodies.Aggregation chimeras were made from embryos of C 57 BL/6 and BALB/c mice.Chimeras and control animals, C 57 BL/6, BALB/c and their reciprocal F1 crosses, were weighed at 8 weeks of age. The mean body weight of chimeras was significantly larger than that of the two inbred strains, and chimeric heterosis for body weight was clearly identified as 16.4% in males and 11.9% in females.Heterosis averaged in the reciprocal F1 crosses was 19.3% in males and 11.5% in females.In the chimeras, proportions of cells from each component strain were estimated by quantitative GPI analyses, using 10 organs (liver, kidney, spleen, stomach, intestine, lung, heart, erythrocyte, testis or ovary and seminal vesicle or uterus).The slight high percentage of BALB/c cells was observed in the mean cell proportions of organs.The linear regression of body weight on degree of chimerism was statistically significant in males (b=-0.083±0.019) and in females (b=-0.062±0.020).
