Carlson J R, Hogness D S
Dev Biol. 1985 Apr;108(2):341-54. doi: 10.1016/0012-1606(85)90038-7.
The Jonah gene family consists of approximately 20 genes, distributed in small clusters at eight or more widely dispersed chromosomal sites. Gene clusters differ in the number of genes per cluster, ranging up to four, and in the arrangement of genes within clusters, which include direct repeats, inverted repeats, and combinations of direct and inverted repeats. In the third-instar larva the Jonah genes are abundantly expressed as transcripts of a single size class, located exclusively in the midgut. The Jonah genes were initially defined by homology to a reference cDNA clone. However, the structural heterogeneity within this gene family is so large that Jonah genes that fail to hybridize to the reference cDNA, yet hybridize to other members of the family that do hybridize to that cDNA have been subsequently identified. These findings raise questions regarding the sharpness of gene family boundaries.
乔纳基因家族由大约20个基因组成，分布在8个或更多广泛分散的染色体位点上的小簇中。基因簇在每个簇中的基因数量（最多可达4个）以及簇内基因的排列方式上存在差异，排列方式包括正向重复、反向重复以及正向和反向重复的组合。在三龄幼虫中，乔纳基因大量表达为单一大小类别的转录本，仅位于中肠。乔纳基因最初是通过与一个参考cDNA克隆的同源性来定义的。然而，这个基因家族内的结构异质性非常大，以至于随后鉴定出了一些乔纳基因，它们不能与参考cDNA杂交，但能与该cDNA杂交的家族其他成员杂交。这些发现引发了关于基因家族边界清晰度的问题。
