Departamento de Xenética, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain.
PLoS One. 2013 Jul 29;8(7):e70067. doi: 10.1371/journal.pone.0070067. Print 2013.
The genomic causes of inbreeding depression are poorly known. Several studies have found widespread transcriptomic alterations in inbred organisms, but it remains unclear which of these alterations are causes of the depression and which are mere responses to the ensuing physiological stress induced by increased homozygosity due to inbreeding. Attempting to differentiate causes from responses, we made a c-DNA microarray analysis of inbreeding depression in Drosophila melanogaster. The rationale of the experiment was that, while depression is a general phenomenon involving reductions in fitness in different inbred lines, its first genetic causes would be different for each inbred line, as they are expected to be caused by the fixation of rare deleterious genes. We took four sets of inbred sublines, each set descending from a different founding pair obtained from a large outbred stock, and compared the expression of the three most depressed sublines and the three least depressed sublines from each set. Many changes in expression were common to all sets, but fourteen genes, grouped in four expression clusters, showed strong set-specific changes, and were therefore possible candidates to be sources of the inbreeding depression observed.
近亲繁殖衰退的基因组原因尚不清楚。一些研究发现，近亲繁殖的生物体中广泛存在转录组改变，但目前仍不清楚这些改变中哪些是衰退的原因，哪些仅仅是由于近亲繁殖导致的同型合子增加而引起的生理压力的反应。为了区分原因和反应，我们对黑腹果蝇的近亲繁殖衰退进行了 cDNA 微阵列分析。实验的基本原理是，虽然衰退是一种普遍现象，涉及不同近亲繁殖系中适应度的降低，但它的第一个遗传原因在每个近亲繁殖系中是不同的，因为它们预计是由罕见的有害基因的固定引起的。我们采用了四组近交亚系，每组都来自于一个大型杂交种群的不同创始对，然后比较了每组中表达最受抑制的三个亚系和表达最不受抑制的三个亚系。许多表达变化在所有组中都是共同的，但有 14 个基因，分为四个表达簇，表现出强烈的组特异性变化，因此可能是观察到的近亲繁殖衰退的来源候选者。
