Genetic Diversity, Structure, and Selective Sweeps in Associated With the Domestication of Cultivated Spinach.

Genotype-by-sequencing (GBS) was used to explore the genetic diversity and structure of , and the selective sweeps involved in domestication of cultivated spinach, , from . A total 7,065 single nucleotide polymorphisms (SNPs) generated for 16 and 76 accessions placed the accessions in one group, 1, and the 76 accessions, which originated from Central Asia, in two distinct groups, 2 and 3. The 2 group shared greater genetic identity with the accessions, 1, than the 3 group. Likewise, the 1 group had a smaller st (0.008) with the 2 group than with the 3 group (st = 0.012), and a greater gene flow (Nm = 30.13) with the 2 group than with the 3 group (Nm = 21.83). The 2 accessions originated primarily from Uzbekistan while the 3 accessions originated mostly from Tajikistan. The Zarafshan Mountain Range appears to have served as a physical barrier that largely separated members of the 2 and 3 groups of . Accessions with admixtures of 2 and 3 were collected primarily from lower elevations at the southern end of the Zarafshan Mountain Range in Uzbekistan. Selective sweep regions identified at 32, 49, and 52 Mb on chromosomes 1, 2, and 3, respectively, appear to have played a vital role in the domestication of as they are correlated with important domestication traits, including day length sensitivity for bolting (flowering). High XP-CLR scores at the 52 Mb genomic region of chromosome three suggest that a selective sweep at this region was responsible for early differentiation of into two groups in Central Asia.