RESULTS: We analyzed 1451 extant genomes, 189 AAs from India and Malaysia, and 43 ancient genomes from S&SEA. Population structure analysis reveals neither language nor geography appropriately correlates with genetic diversity. The inconsistency between "language and genetics" or "geography and genetics" can largely be attributed to ancient admixture with East Asian populations. We estimated a pre-Neolithic origin of AA language speakers, with shared ancestry between Indian and Malaysian populations until about 470 generations ago, contesting the existing model of Neolithic expansion of the AA culture. We observed a spatio-temporal transition in the genetic ancestry of SEA with genetic contribution from East Asia significantly increasing in the post-Neolithic period.
CONCLUSION: Our study shows that contrary to assumptions in many previous studies and despite having linguistic commonality, Indian AAs have a distinct genomic structure compared to Malaysian AAs. This linguistic-genetic discordance is reflective of the complex history of population migration and admixture shaping the genomic landscape of S&SEA. We postulate that pre-Neolithic ancestors of today's AAs were widespread in S&SEA, and the fragmentation and dissipation of the population have largely been a resultant of multiple migrations of East Asian farmers during the Neolithic period. It also highlights the resilience of AAs in continuing to speak their language in spite of checkered population distribution and possible dominance from other linguistic groups.
Methods: Retrospective review of R-EBUS transbronchial biopsy for PPL over 17 months.
Results: 114 R-EBUS scans were included for analysis during the study period. Forceps biopsy was performed in 76 (66.7%) cases and cryobiopsy in 38 (33.3%) cases. Baseline demographics and lesion characteristics did not differ between the two groups. Median (interquartile range) lesion size was 3.48 (2.63-4.51) cm. Overall, 41.2% of lesions were of eccentric orientation and 15.8% adjacent orientation; only 43% were concentric in orientation. Overall diagnostic yield was 67.5% (77 out of 114). Orientation remained an important factor affecting diagnostic yield. Transbronchial cryobiopsy significantly increased the diagnostic yield in eccentrically and adjacently orientated lesions to 75.0% (18 out of 24), compared to 48.8% (20 out of 41) obtained via forceps biopsy (p<0.05); but not in concentric lesions. Cryobiopsy was associated with more mild and moderate bleeding complications compared to the forceps biopsy group.
Conclusions: Transbronchial cryobiopsy under R-EBUS guidance is a safe procedure which potentially increases diagnostic yield in eccentrically and adjacently orientated PPLs.