Glombik Marek, Arunkumar Ramesh, Burrows Samuel, Mogg Sophie Louise, Wang Xiaoming, Borrill Philippa
Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
School of Life Sciences, Technical University of Munich, Alte Akademie 8, Freising, 85354, Germany.
Genome Biol. 2025 May 28;26(1):147. doi: 10.1186/s13059-025-03598-3.
Differences in the relative level of expression of homoeologs, known as homoeolog expression bias, are widely observed in allopolyploids. While the evolution of homoeolog expression bias through hybridization has been characterized, on shorter timescales such as those found in crop breeding programs, the extent to which homoeolog expression bias is preserved or altered between generations remains elusive.
Here we use biparental mapping populations of hexaploid wheat (Triticum aestivum) with a common "Paragon" parent to explore the inheritance of homoeolog expression bias in the F generation. We found that homoeolog expression bias is inherited for 26-27% of triads in both populations. Most triads conserved a similar homoeolog expression bias pattern as one or both parents. Inherited patterns were largely driven by changes in the expression of one homoeolog, allowing homoeolog expression bias in subsequent generations to match parental expression. Novel patterns of homoeolog expression bias occurred more frequently in the biparental population from a landrace × elite cross, than in the population with two elite parents.
These results demonstrate that there is significant reprogramming and stabilization of homoeolog expression bias within a small number of generations that differs significantly based on the parental lines used in the crossing.
同源基因相对表达水平的差异，即同源基因表达偏向，在异源多倍体中广泛存在。虽然通过杂交产生的同源基因表达偏向的进化已得到表征，但在较短的时间尺度上，如在作物育种计划中，同源基因表达偏向在世代间保持或改变的程度仍不清楚。
在这里，我们使用具有共同“Paragon”亲本的六倍体小麦（普通小麦）双亲作图群体，来探究F代中同源基因表达偏向的遗传情况。我们发现，在两个群体中，26% - 27%的三联体的同源基因表达偏向是可遗传的。大多数三联体保留了与一个或两个亲本相似的同源基因表达偏向模式。遗传模式在很大程度上是由一个同源基因表达的变化驱动的，使得后代中的同源基因表达偏向与亲本表达相匹配。与具有两个优良亲本的群体相比，来自地方品种×优良品种杂交的双亲群体中，同源基因表达偏向的新模式出现得更频繁。
这些结果表明，在少数几代内，同源基因表达偏向存在显著的重编程和稳定现象，且根据杂交所用的亲本系不同而有显著差异。
