Osborne B A, Golde T E, Schwartz R L, Rudikoff S
Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst 01003.
Genetics. 1988 Aug;119(4):925-31. doi: 10.1093/genetics/119.4.925.
To examine questions of immunoglobulin gene evolution, the IgA alpha heavy chain gene from Mus pahari, an evolutionarily distant relative to Mus musculus domesticus, was cloned and sequenced. The sequence, when compared to the IgA gene of BALB/c or human, demonstrated that the IgA gene is evolving in a mosaic fashion with the hinge region accumulating mutations most rapidly and the third domain at a considerably lower frequency. In spite of this pronounced accumulation of mutations, the hinge region appears to maintain the conformation of a random coil. A marked propensity to accumulate replacement over silent site changes in the coding regions was noted, as was a definite codon bias. The possibility that these two phenomena are interrelated is discussed.
为了研究免疫球蛋白基因进化的问题，来自小家鼠进化上亲缘关系较远的旁系物种印度姬鼠的IgAα重链基因被克隆并测序。与BALB/c或人类的IgA基因相比，该序列表明IgA基因以镶嵌方式进化，铰链区积累突变的速度最快，而第三个结构域的突变频率则低得多。尽管有明显的突变积累，但铰链区似乎保持了无规卷曲的构象。在编码区观察到在替换位点而非沉默位点积累突变的明显倾向，以及明确的密码子偏好。讨论了这两种现象相互关联的可能性。
