Introduction

The identification of unknown human remains is a fundamental and ethical obligation, enshrined in both domestic and international law. The right to retain one’s identity after death is universally recognized and critical to mitigate psychological impact of ambiguous loss, where families remain in a state of uncertainty, not knowing whether their loved ones are dead or alive [1–4]. In mass fatality events and migration-related disasters, identification is essential not only for humanitarian reasons but also for legal and administrative purposes.

Despite international guidelines and best practices [5, 6] identifying highly degraded human remains from large-scale events -such as maritime disasters, armed conflicts, or human rights violations- remains challenging due to the complexity of the context. Factors such as the number of remains, the degree of disarticulation [7], and severe DNA degradation significantly affect the success of identification efforts [8]. This is particularly true for deeply compromised remains [9] and for maritime fatalities, where bodies submerged at sea undergo rapid post-mortem changes, including the loss of most hair and teeth and structural alterations to bone tissue.

Bones and teeth are among the most durable biological materials and often represent the only source of genetic material in these cases. However, sampling these elements is inherently invasive and compromises the integrity of the skeleton, which is crucial for anthropological assessment and respectful restitution. Preserving cranial integrity is especially important when bone lesions are present or when further analyses are required. As scientists and custodians of human dignity, we have a responsibility to minimize the impact of sampling and align identification practices with ethical and cultural expectations.

Despite major advances in forensic genetics, DNA sampling from skeletal remains still largely relies on destructive procedures that permanently alter the skull or other key skeletal elements. While these approaches maximize DNA yield, they conflict with humanitarian principles particularly in mass fatality and migration-related contexts [5, 6, 10] and limit subsequent anthropological or odontological analyses. In humanitarian operations, identification teams are increasingly required to balance analytical effectiveness with respect for human remains and the expectations of families, communities, and legal frameworks [1, 2].

Alternative skeletal elements such as the petrous bone and auditory ossicles have been previously investigated as sources of genetic material, primarily in archaeological contexts or isolated forensic casework. However, their systematic integration into standardized workflows for DVI in humanitarian settings remains limited [11–17] This gap underscores the need for validated strategies that combine technical robustness with ethical and operational sustainability.

In this study, we evaluated two minimally invasive genomic sampling approaches -auditory ossicles and petrous micro-sampling- for Short Tandem Repeats (STRs) profiling in highly degraded skeletal remains recovered from the April 18, 2015, Mediterranean shipwreck. While auditory ossicles have previously been investigated as an optimal DNA source for ancient samples [11] and for identification of highly putrefied cadavers [12], and petrous bones have recently been evaluated for forensic STR typing [13, 15, 18], their application to highly degraded skeletal remains recovered after prolonged marine submersion remains limited. Here, we specifically assessed these minimally invasive approaches in remains submerged at sea for approximately one year, providing insight into their performance under extreme environmental conditions relevant to real DVI scenarios. Beyond DNA profiling performance, we examined the implications of these methods for skeletal preservation and their integration into humanitarian identification protocols. By demonstrating that reliable genetic profiles can be obtained without highly destructive sampling, this work supports a shift toward minimally invasive, dignity-centered workflows in mass fatality management and humanitarian response.