SGER: Evolution of Major Histocompatibility Complex (MHC) Class I and II Genes in the American Crow (Corvus brachyrhynchos) Following an Epidemic of West Nile Virus

1999年，西尼罗河病毒(WNV)抵达纽约，导致美洲乌鸦(Corvus Brachyribrnchos)大量死亡。自1990年以来，汤普金斯县对乌鸦进行了研究，并提供了用于提取DNA的血液样本。由于西尼罗河病毒很有可能在2001年夏天在纽约州北部达到流行病的程度，可以预见乌鸦会有大规模的死亡。这提供了一个独特的机会来确定哪些人可以在感染西尼罗河病毒后存活下来，并确定耐药性的遗传成分。在2000-2001年冬季将捕获大量乌鸦，并将采集血液样本进行DNA分析和血清学检测。DNA样本将通过分析免疫反应基因的差异，从而为研究预期的西尼罗河病毒疫情爆发前后的遗传多样性提供基础。如果在西尼罗河病毒疫情中幸存下来的乌鸦在与免疫反应相关的基因的等位基因频率上存在差异，这一假说将得到验证。虽然人们假设病原体与宿主共同进化以产生有效的免疫反应，但很少有使用自然种群的研究检验这一假设的有效性。为了了解人群在感染新疾病时面临的风险，重要的是比较接触新病原体之前和之后的人群。

Schat0104795In 1999 West Nile virus (WNV) reached New York causing massive mortality in American Crows (Corvus brachyrhynchos). In Tompkins County crows have been studied since 1990, and blood samples for DNA extraction are available. Since WNV will most likely reach epidemic proportions in upstate NY in the summer of 2001, massive mortality can be expected among crows. This provides a unique opportunity to determine which individuals can survive infection with WNV and identify the genetic component of the resistance. Large numbers of crows will be captured in the 2000-2001 winter and blood samples will be obtained for DNA analysis and serology. DNA samples will be analyzed for differences in immune response genes by, thus providing the basis to study genetic diversity before and after the onset of the expected WNV epidemic. The hypothesis will be validated if crows surviving the WNV epidemic differ in allele frequencies of genes associated with immune responses. Although it is assumed that pathogens co-evolve with the ability of the host to mount effective immune responses, very few studies using natural populations have tested the validity of this hypothesis. In order to understand the risks to which populations are exposed when a new disease infects them, it is important to compare populations before and after they are exposed to the new pathogen.