Does inbreeding affect gene expression in birds?

Inbreeding increases homozygosity, exposes genome-wide recessive deleterious alleles and often reduces fitness. The physiological and reproductive consequences of inbreeding may be manifested already during gene regulation, but the degree to which inbreeding influences gene expression is unknown in most organisms, including in birds. To evaluate the pattern of inbreeding-affected gene expression over the genome and in relation to sex, we performed a transcriptome-wide gene expression (10 695 genes) study of brain tissue of 10-day-old inbred and outbred, male and female zebra finches. We found significantly lower gene expression in females compared with males at Z-linked genes, confirming that dosage compensation is incomplete in female birds. However, inbreeding did not affect gene expression at autosomal or sex-linked genes, neither in males nor in females. Analyses of single genes again found a clear sex-biased expression at Z-linked genes, whereas only a single gene was significantly...

近交（Inbreeding）可提升个体纯合性（Homozygosity），暴露全基因组（Genome-wide）范围内的隐性有害等位基因，且通常会降低适合度（Fitness）。近交带来的生理与繁殖后果可能早在基因调控阶段便已显现，但在包括鸟类在内的多数生物中，近交对基因表达的影响程度仍未明确。为探究全基因组范围内受近交调控的基因表达模式及其与性别的关联，我们对10日龄近交系与远交系的雄性、雌性斑胸草雀脑组织开展了全转录组基因表达（Transcriptome-wide gene expression）分析，本次分析共涵盖10695个基因。研究发现，Z连锁基因（Z-linked genes）在雌性个体中的表达量显著低于雄性，这证实了鸟类雌性的剂量补偿（Dosage Compensation）机制并不完全。然而，无论在雄性还是雌性个体中，近交均未对常染色体（Autosomal）或性连锁基因的基因表达产生显著影响。单基因分析同样证实了Z连锁基因存在显著的性别偏向性表达（Sex-biased expression），但仅有单个基因呈现出显著的……