Collecting DNA samples in the field

Collecting DNA samples in the field requires careful planning, attention to detail, and adherence to ethical and legal considerations. Here are some procedures for collecting DNA samples in the field:

● Select Suitable Samples: Identify potential sources of DNA, such as hair, scat (feces), saliva, blood, or tissue. Focus on non-invasive sampling methods to minimize harm to the animals.

● Use Sterile Equipment: Use clean, disposable gloves and sterile sampling tools to prevent contamination of the DNA samples.

● Minimize Handling: Minimize direct contact with the samples to avoid transferring human DNA onto the collected material.

● Hair Samples: When collecting hair samples, use clean forceps or tweezers to gently pluck a few hairs from areas where they are loosely attached to the animal's body, such as shedding or caught on branches.

● Scat Samples: Use a clean spatula or scoop to collect a small portion of the scat. Avoid touching the sample with your hands.

● Saliva or Blood Samples: If collecting saliva or blood, use swabs or a sterile needle and syringe to obtain the sample from wounds or areas where the animal has recently left saliva.

● Tissue Samples: Collecting tissue samples requires specific training and permits in many jurisdictions. It is best to leave tissue collection to professionals with the necessary expertise.

● Labeling and Documentation: Properly label each sample with information such as the date, time, location, species (if known), and any relevant observations. Keep detailed field notes for each sample collected.

● Preservation: Store the samples in appropriate containers and preservatives to maintain DNA integrity. Commonly used preservatives include silica gel, ethanol, or specialized DNA preservation solutions.

● Chain of Custody: If the samples are for scientific research or legal purposes, establish and maintain a proper chain of custody to ensure the integrity of the evidence.

● Permits and Regulations: Familiarize yourself with local regulations and obtain any necessary permits for collecting DNA samples from wildlife.

● Ethical Considerations: Collect DNA samples with respect for the animals and their habitats. Minimize disturbance and harm to the species and ecosystem.

● Collaborate with Experts: If you are unsure about proper DNA sampling techniques or require specialized analysis, collaborate with experts in the field of genetics and DNA research.

● Data Sharing: Consider sharing your DNA samples and data with reputable research institutions or experts to contribute to a broader understanding of wildlife genetics.

Remember that collecting DNA samples from wildlife requires special attention and prudence. Consult subject-matter experts or relevant wildlife authorities if you are uncertain about appropriate procedures or concerned about the outcomes of your sample.

Environmental DNA sampling

By gathering and examining DNA that organisms shed or release into the environment, environmental DNA (eDNA) sampling is a non-invasive technique for finding and studying the presence of organisms in their natural habitats. Because the eDNA approach can identify species without requiring physical capture or direct observation, it has become more popular in the fields of ecology, conservation biology, and environmental monitoring.

Here's how eDNA sampling works:

● DNA Shedding: All living organisms continuously shed DNA into their environment through various biological materials, such as skin cells, feces, urine, mucus, and hair.

● Sample Collection: Environmental DNA sampling involves collecting water, soil, sediment, or air samples from the environment where the target species might be present.

● Filtering and Extraction: In aquatic environments, water samples are typically filtered to capture the eDNA, while in terrestrial environments, soil and sediment samples are processed to extract the eDNA.

● PCR Amplification: Polymerase chain reaction (PCR) is then used to amplify and replicate the target species' DNA fragments, making them detectable.

● Species Identification: Once amplified, the DNA is sequenced and compared to existing DNA databases to identify the species present in the sample.

Environmental DNA sampling offers several advantages:

● Non-invasive: It does not require direct contact with the target species, reducing disturbance and potential harm to the animals.

● Sensitive: eDNA sampling can detect even rare or elusive species that might be challenging to observe directly.

● Efficient: It allows researchers to survey large areas quickly, increasing the efficiency of species detection.

● Early Detection: It can be used for early detection of invasive species or endangered species monitoring.

● Biodiversity Assessment: It provides valuable information on species presence and distribution, contributing to biodiversity assessments. However, eDNA sampling also has some limitations:

● Detection Limit: The technique might not detect species that are present in low abundance or have limited shedding rates.

● Degradation: Environmental DNA can degrade over time, limiting the detection window for some species.

● Contamination: Contamination from other sources can lead to false positives or inaccurate results.

● Lack of Species-Specificity: The eDNA collected might belong to closely related species, requiring further analysis for accurate identification.

Despite these drawbacks, eDNA sampling is a useful tool for ecological and conservation study, and it is constantly developing thanks to new techniques and technologies. It advances our knowledge of species distribution and ecosystem dynamics and serves as a supplement to conventional field survey techniques.