Breathing air and living underwater: molecular evolution of genes related to oxidative response in aquatic mammals

• Grant number: 20/03588-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2020
• End date: April 30, 2021
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Mariana Freitas Nery
• Grantee: Giovanna Selleghin Veiga
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

There are three independent mammalian lineages that secondarily returned to the aquatic environment: cetaceans, pinnipeds and sirenians. During their evolutionary histories, several morphological, physiological and behavioral modifications evolved, such as the ability of diving in apnea and the vasoconstriction of some organs to make the use of oxygen more efficiently during diving, resulting in the hypoxia of some tissues (liver, kidneys and spleen). The adaptations for coping with hypoxia are well established and it is known that HIF-1± gene plays a fundamental role. After long dives, the first breath out of water generates the reperfusion of these tissues, what should lead to the production of reactive oxygen species (ROS), via xanthine dehydrogenase (XDH) and oxidative stress. However this oxidative stress is not observed in the aforementioned aquatic mammalian lineages, mainly due to the role of antioxidant enzymes such as GPx, GR, CuZn -SOD, catalase and peroxiredoxins that are highly active in the cells of these animals. Accordingly, in this project, we aim to study the genetic basis that comprise the maintenance of homeostasis during reperfusion in aquatic mammals. Our goal is to unravel the molecular evolution of these genes (GPX, GSR, SOD1, CAT, PRDX1/PRDX3 and XDH) in the lineages of animals that go through a chronic hypoxia/ reperfusion process.