位置效应一个基因随染色体岐变而改变它与邻近基因的位置关系从而改变表型效应的现象
The positional effect refers to the phenomenon where a gene changes its positional relationship with adjacent genes due to chromosomal mutations, thereby altering its phenotypic effect
以上为机器翻译结果，长、整句建议使用 人工翻译 。