According to research on the major histocompatibility complex (MHC) in Indo-Pacifian humpback dolphins (Sousa chinensis), immune systems have a crucial role in how terrestrial and aquatic mammals are selected.
Research Findings
In the study, 32 Sousa Chinesis from the Pearl River Estuary were examined for the expression and sequence polymorphism of two Major Histocompatibility Complex class II genes (DQB and DRB). According to the inquiry, sousa chinensis are susceptible to a mechanism of balancing selection because of the high ratio of synonymous to non-synonymous substitution rates, codon-based selection analyses, and TSP (trans-species polymorphism).
Importance of Genetic Variations
It is of critical importance to understand the level of genetic variations and the way threatened species maintain their genetic variations. This information helps biologists to come up with ways to avoid loss of lives by organisms belonging to small populations. When organisms belonging to small populations lose their genetic variation, they face an increased chance of extinction because their reproductive capabilities are hampered and become more prone to illnesses. Previously, conservationists and biologists depended on the DNA strand including the mitochondrial DNA to address the issue of genetic diversity on organisms threatened with extinction. Research has shown that the arrangement of neutral genetic variation in organisms sometimes fails to show a relationship with the quantifiable variation for traits that determine the ecological fitness of organisms or the variation of genes that are important for the adaptability of organisms (Knopp et al. 2007).
Background
The MHC genes have been relied upon as indicators of adaptive capabilities in organisms in different researches. The genes (MHC) represent the most polymorphic genes in animals with a backbone, which create coded data from a series of glycoproteins that come up with an enhanced organism that can adapt to different ecosystems and be immune to existence-threatening illnesses (Piertney and Oliver 2006).S Chinensis is known as the Chinese white dolphin and was mostly found on the coastal and inshore water bodies in the Indian and Western Pacific Oceans. Over time, this dolphin species population has declined considerably. It is listed as one of the organisms that need protection from extinction in the First Order of the National Key Protected Wild Aquatic Animals List in China. The species has also received international protection due to the declining numbers of its population. Today, the most numerous population of the species is found in the Pearl River Estuary and consists of about one thousand five hundred individuals (Jefferson and Hung 2004). All other areas that have the S chenensis population make up about three-hundred individuals of the organism. The present study sought to investigate the expression and diversity of two specific MHC genes (DQB and DRB) in the Chinese white dolphins in the Pearl River Estuary. This study carefully evaluated the basic genetic factors that contributed to the differentiation of MHC gene in S chenesis. The ultimate goal was to come up with a more effective means of conserving s chenensis.
Materials and Methods
Skin samples as well as muscle samples were taken from individual dolphins in the Pearl River Estuary. Of the 32 samples taken in this region, no significant variation of the genetic make-up was fond in these organisms. In addition, samples from dead individuals were taken such as blood, bodily fluids and other samples from stranded dolphins. The samples were preserved for research at Sun Yat-sen University.
MHC Expression
In many studies on the genetics of organisms, marine mammals have showed a relatively low level of MHC compared to their terrestrial counterparts (Murray and White 1998; Yang et al. 2005; Xu et al. 2009). In the Chinese white dolphins, the MHC genes depicted an interrupted reading frame which illustrated a deficiency in the MHC function or the result of weakened pathogenic prevalence in the oceanic ecosystem. From the study, the S chenensis showed a low variation in the MNH class II genes. Both DBQ and DRB alleles was as low in Schenensis as it is in the P sinus of California harbor. The P sinus numbers have been declining globally and stand at slightly over 567 individuals today.
