MHC genotype and near-deterministic mortality in grey seals

Area of Science:

• Immunology
• Marine Mammal Biology
• Population Genetics

Background:

• The Major Histocompatability Complex (MHC) plays a known role in immunity and recognition.
• Its precise importance relative to other immune components is not fully understood.
• Marine mammals like the grey seal often exhibit low MHC allelic diversity.

Purpose of the Study:

• To investigate the critical role of MHC in immune system function and survival.
• To determine the impact of MHC genotype diversity on pup survivorship in grey seals.
• To quantify the contribution of MHC to overall mortality in a low-diversity species.

Main Methods:

• Comparison of MHC genotype frequencies between grey seal pups and adults.
• Analysis of the association between specific MHC alleles and pup survival rates.
• Statistical modeling to estimate the proportion of mortality attributable to MHC diversity.

Main Results:

• One specific MHC allele was strongly linked to pup survival; absence increased mortality risk.
• The total number of MHC alleles was a significant predictor of survivorship to adulthood.
• Approximately 70% of pup mortality was estimated to be attributable to MHC-related factors.

Conclusions:

• Despite low allelic diversity, the MHC is critically important for grey seal pup survival.
• MHC diversity is a key determinant of whether pups survive disease and reach adulthood.
• This research underscores the vital, yet often underestimated, role of MHC in population health and resilience.