Khongsdier R, Mukherjee Nandita
Department of Anthropology, North-Eastern Hill University, Shillong, India.
Ann Hum Biol. 2003 Sep-Oct;30(5):605-21. doi: 10.1080/03014460310001592669.
It is generally believed that improvement in environmental quality is the main factor responsible for the better growth and nutritional status of children in developing countries. However, it is still not clear whether this better growth performance is also associated with heterosis and/or gene flow that may take place as a result of the geographical movement of individuals, or migration.
The present paper attempts to examine the effects of heterosis on physical growth of girls in height and its segments.
A cross-sectional sample of the Khasi girls of Shillong in Northeast India was considered in the present analysis. The height and sitting height of 1368 girls aged 3-18 years were measured with a Harpenden anthropometer, following standard techniques. The sample was divided into two groups, namely hybrid (HB) and non-hybrid (NHB) girls,in order to test the effects of heterosis using analysis of covariance with the household income as a covariate. The Preece-Baines model I (M. A. Preece and M. F. Baines, Annals of Human Biology, 5, 1-24, 1978) was used to fit the adjusted means of height and its segments with a view to assess the variation in adult height, age at peak velocity and size at peak velocity.
Both HB and NHB girls were similar in age at maximum increment for height(12 years) and sitting height (13 years), although it was much earlier in the former(10.5 years) than in the latter (11.9 years) with respect to subischial length. The results indicated that HB girls were larger than NHB girls across ages. Such a higher anthropometric status in HB girls was mainly due to their higher growth velocities before the adolescent period. The effect of heterosis after household income was highly significant at many ages from 6 to 18 years, although it was not clearly perceptible in the case of subischial length.
Subject to further studies, the role of heterosis and/or gene flow in influencing growth and development of children cannot be completely ruled out, especially after 5 years of age when the variation in growth patterns is likely to be associated not only with environmental quality but also with genetic mechanisms.
人们普遍认为，环境质量的改善是发展中国家儿童生长发育更好、营养状况更佳的主要因素。然而，目前尚不清楚这种更好的生长表现是否也与杂种优势和/或基因流动有关，而杂种优势和/或基因流动可能是由于个体的地理迁移或移民而发生的。
本文试图研究杂种优势对女孩身高及其各部分身体生长的影响。
本分析采用印度东北部西隆卡西族女孩的横断面样本。按照标准技术，使用哈彭登人体测量仪测量了1368名3至18岁女孩的身高和坐高。为了以家庭收入作为协变量，通过协方差分析来检验杂种优势的影响，将样本分为两组，即杂交（HB）女孩和非杂交（NHB）女孩。采用普里斯-贝恩斯模型I（M.A.普里斯和M.F.贝恩斯，《人类生物学纪事》，第5卷，第1 - 24页，1978年）来拟合身高及其各部分的调整均值，以评估成年身高、身高增长峰值年龄和身高增长峰值时的大小变化。
HB和NHB女孩身高最大增长年龄（12岁）和坐高最大增长年龄（13岁）相似，尽管就坐骨下长度而言，前者（10.5岁）比后者（11.9岁）要早得多。结果表明，各年龄段HB女孩都比NHB女孩体型更大。HB女孩这种较高的人体测量学状态主要归因于她们在青春期前较高的生长速度。在家庭收入之后，杂种优势的影响在6至18岁的许多年龄段都非常显著，尽管在坐骨下长度方面不太明显。
有待进一步研究，杂种优势和/或基因流动在影响儿童生长发育方面的作用不能完全排除，尤其是在5岁之后，此时生长模式的变化可能不仅与环境质量有关，还与遗传机制有关。
