abg_emp_hmp: microbial source tracking of New York African Burial Ground soils against EMP and HMP reference cohorts

Reproducible analysis scripts for microbial source tracking of centuries-old burial soils from the New York African Burial Ground (NYABG). The pipeline compares NYABG burial microbiomes (70 burial samples, 6 controls) with Earth Microbiome Project (17,482 environmental samples) and Human Microbiome Project (4,743 body-site samples) reference cohorts at genus level. Includes FEAST source tracking, IndVal indicator species, ANCOM-BC2 and ALDEx2 differential abundance with cross-method consensus, body-site classification, decontamination, and a full sensitivity-and-robustness battery covering rarefaction depth, prevalence filter thresholds, body-region confounds, pseudoreplication, cranial proximity, soil matrix partitioning, and EMP holdout null distributions.