University of Nebraska, School of Biological Sciences, Lincoln, NE 68588, USA.
Sci Adv. 2020 Jun 17;6(25):eabb5447. doi: 10.1126/sciadv.abb5447. eCollection 2020 Jun.
Developmental shifts in stage-specific gene expression can provide a ready mechanism of phenotypic change by altering the rate or timing of ontogenetic events. We found that the high-altitude Tibetan antelope () has evolved an adaptive increase in blood-O affinity by truncating the ancestral ontogeny of globin gene expression such that a high-affinity juvenile hemoglobin isoform (isoHb) completely supplants the lower-affinity isoHb that is expressed in the adult red blood cells of other bovids. This juvenilization of blood properties represents a canalization of an acclimatization response to hypoxia that has been well documented in adult goats and sheep. We also found the genomic mechanism underlying this regulatory isoHb switch, revealing how a reversible acclimatization response became genetically assimilated as an irreversible adaptation to chronic hypoxia.
发育阶段特异性基因表达的转变可以通过改变个体发育事件的速度或时间来提供表型改变的现成机制。我们发现，高原藏羚羊（）通过截断珠蛋白基因表达的祖先发育，从而进化出对血液-O 亲和力的适应性增加，使得高亲和力的幼体血红蛋白同工型（isoHb）完全取代了在其他牛科动物的成年红细胞中表达的低亲和力同工型（isoHb）。这种血液特性的幼态化代表了对缺氧的适应反应的定型，在成年山羊和绵羊中已有很好的记录。我们还发现了这种调节性 isoHb 开关的基因组机制，揭示了如何将一种可逆的适应反应遗传同化，成为对慢性缺氧的不可逆适应。
