Data from: Phylogeography of Sophora moorcroftiana supports Wu’s hypothesis on the origin of Tibetan alpine flora

Wu hypothesized that the Tibetan flora originated mostly from the
paleotropical Tertiary flora in the Hengduan Mountains by adapting to the
cold and arid environments associated with the strong uplift of the
Qinghai-Tibet Plateau (QTP). Here, we combine the phylogeographic history
of Sophora moorcroftiana with that of S. davidii to explore the speciation
of S. moorcroftiana to test this hypothesis. We collected 151 individuals
from 17 populations and sequenced two chloroplast fragments and the
internal transcribed spacer of rDNA. Five chlorotypes and nine ribotypes
were detected but no significant phylogeographic structure was revealed.
The integrated results of phylogeographic studies of these two species
clearly support the progenitor-derivative relationship between them. We
infer that the western peripheral population of S. davidii migrated
westwards from the Hengduan Mountains to the middle reaches of the Yarlung
Zangbo River and differentiated from its ancestor in the process of
adaptation to increasingly cold and arid environments with the uplift of
the QTP and finally evolved into S. moorcroftiana during the Late
Pliocene. In addition, our findings shed light on the idea that natural
selection, as imposed by climate differentiation (especially mean diurnal
range and precipitation seasonality), directly drove this peripatric
speciation event after geographic isolation. The speciation of S.
moorcroftiana is a strong case supporting Wu’s hypothesis about the origin
of Tibet’s flora.