Researchers identify genetic drivers behind spruce tree diversification

Researchers from Lanzhou University and the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences identified the genetic mechanisms that shaped the evolution of the Picea genus, which includes many spruce trees found across the Northern Hemisphere.

The team analyzed transcriptomic data from 37 different species to understand how these trees diversified into different regional types. The scientists used a pan-transcriptomic framework to manage the complex repetitive sequences common in conifer genomes.

Their analysis revealed that incomplete lineage sorting, a process occurring during rapid speciation in large populations, caused most of the conflicting genetic signals in the genus. This process accounted for about 28 percent of the conflict, while hybridization only accounted for about 7 percent.

The team also found that only about 9 percent of spruce genes are shared by all species to perform basic cellular functions, while 90 percent of genes vary between species to help them adapt to specific environments. The study identified four major spruce groups and found that Picea breweriana, a rare species from western North America, is the earliest-diverging lineage.

The researchers also linked specific gene changes to regional climates, such as low-oxygen response genes in lineages on the Qinghai-Tibet Plateau and photosynthesis adaptations in boreal lineages. Sun Yongshuai of XTBG stated that these findings suggest conservationists should protect genetically diverse populations to help trees adapt to climate change.