Microbial Analysis of the long-living Aldabra Giant Tortoises

SOKENDAI研究派遣プログラム 採択年度: 2022

Douaa Zakaria


Aldabra Giant Tortoises in Parco Natura, Verona, Italy

This is one of the oldest Aldabra Giant Tortoises in Italy (>100 years old) and I’m looking forward to find the link between its microbiome, diet and longevity.

Longevity is a complex trait determined by both genetic and environmental factors. The bacteria residing intestines named as gut microbiota have been speculated to be a determinant factor due to their impact on immunity and metabolism. An interesting example to study microbiota-longevity link is Aldabra Giant Tortoises that can live up to 200 years. Their longevity is outstanding in comparison with their relative species and many are kept in a controlled environments where diet is a fixed parameter, making it easier to focus on the microbiota-longevity link. So far, only two papers have addressed the microbiome composition of Aldabra Giant Tortoise, and the authors, the Mattarelli group in University of Bologna, are my host in Italy.

During my visit, I worked on 53 fecal samples from Aldabra Giant Tortoises found in controlled and wild environments. I analyzed the bacterial composition of these samples using R (a programing tool for statistical analysis) to understand the similarities and differences between different age groups and how that is correlated with the environmental factors.

The results show that the impact of diet and habitat on gut microbial composition weigh much more than the impact of age. However, we found some bacterial phyla to be enriched in centenarian tortoises in comparison with younger ones.

Later, our collaborators will perform metagenomic sequencing that provides more detailed information about the functional composition of tortoises’ microbiota and how it can affect metabolism and in turn longevity. The results can then be compared with the microbial composition of human centenarians to find out common bacteria that can extend lifespan in a healthy manner.


Date of Departure: 2023/12/01
Date of Return: 2023/01/23


Bologna, Italy


University of Bologna

Dr. Paola Mattarelli


I worked with people in wet laboratories and learned more about the process of 16s rRNA sequencing. Moreover, I had the chance to visit Parco Natura, where many giant tortoises live, to ask their keepers about their diet and lifestyle and link that to the results we obtained from their microbial fecal samples. I also established a new collaboration with Segata laboratory at University of Trento for the metagenomic sequencing.

Department of Genetics. Douaa Zakaria

I am a D3 student in the Biological Networks Laboratory of National Institute of Genetics, working on bioinformatic analysis for the last three years. Originally from Syria, I studied Molecular Biology and Genetics in Turkey before I moved to Japan for my Ph. D. study. I really enjoy visiting different countries, getting exposed to new cultures and interacting with people from various backgrounds.