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Ecological land is a type of land that has considerable ecological value. Understanding the evolution of urban ecological land in Zhuhai, China, holds great significance for revealing the evolution of ecological land in the Dawan District of southern China. We explored the temporal and spatial variation in urban ecological land in Zhuhai using the transformation matrix, equivalent ecological land, landscape index and ecological land center of gravity migration methods. Multivariate logistic regression was used to analyze the mechanism of ecological land change, and a transition probability map of the ecological land in the study area was drawn. The results showed the following. (1) From 1991 to 2018, the area of ecological land in Zhuhai city continuously decreased, with a reduction in area of 274.8 km2, or 32.3%. Sharp changes mainly occurred from 1991 to 2000. (2) The ecological land in the study area has gradually become fragmented, and the degree of landscape heterogeneity has increased. Affected by the expansion of the outer edge of the city to the southwest and the construction of ecological land within the city, the center of gravity of the ecological land has shifted to the northeast by 1346 m. (3) The elevation, slope, distance from built-up land and growth rate of built-up land are important factors influencing the transformation of ecological land. In the future, rivers and shallow coastal waters, tidal flats, and grasslands in the study area have the highest probability of transformation. The Jinwan District and Xiangzhou District will face severe ecological land protection pressure. The method of spatial–temporal analysis of urban ecological land developed in this paper can be applied in similar studies on other cities, and the results obtained for Zhuhai, China, have reference value for future urban planning and ecological protection work.

Previous studies have linked the WNT pathway and human skeleton formation; therefore, genes related to WNT might contribute to the onset and development of osteoporosis. In this study, we investigated the potential genetic association of WLS, which encodes an important mediator in the WNT pathway, with osteoporosis and its related quantitative traits in a sample of 6,620 individuals from Han Chinese population. A two-stage approach, with a discovery stage with 859 cases and 1,690 controls and a validation stage with 1,039 cases and 3,032 controls, was applied in the study. Forty SNPs were genotyped in the discovery stage. The intronic SNP rs2566752 was identified to be significantly associated with osteoporosis (ORdiscovery = 0.78, Pdiscovery = 3.73 × 10−5; ORvalidation = 0.80, Pvalidation = 1.96 × 10−5). Two SNPs surrounding rs2566752 (in addition to this SNP itself) were identified to be associated with bone mineral density. In addition, we have identified a 20 kb peak region of H3K27Ac histone mark enrichment between rs2772304 and rs2566752. Our study suggested that WLS is an important locus for osteoporosis and its related quantitative phenotypes in Han Chinese population. Additional sequencing-based studies are needed to investigate the genetic architecture of this regulatory region and its relationship with osteoporosis-related phenotypes.

Osteoporosis is a systemic skeletal disorder characterized by reduced bone mineral density (BMD) and disrupted bone architecture, predisposing the patient to increased fracture risk. Evidence from early genetic epidemiological studies has indicated a major role for genetics in the development of osteoporosis and the variation in BMD. In this study, we focused on two key genes in the endochondral ossification pathway, IBSP and PTHLH. Over 9,000 postmenopausal Han Chinese women were recruited and 54 SNPs were genotyped. Two significant SNPs within IBSP, rs1054627 and rs17013181, were associated with BMD and postmenopausal osteoporosis by the two-stage strategy and rs17013181 was also significantly associated with serum IBSP levels. Moreover, one haplotype (rs12425376-rs10843047-rs42294) covering the 5’ end of PTHLH was associated with postmenopausal osteoporosis. Our results provide evidence for the association of these two key endochondral ossification pathway genes with BMD and osteoporosis in postmenopausal Han Chinese women. Combined with previous findings, we provide evidence that a particular SNP in IBSP has an allele-specific effect on mRNA levels, which would, in turn, reflect serum IBSP levels.