|XU, LINGYANG - University Of Maryland|
|HE, YANGHUA - University Of Maryland|
|DING, YI - University Of Maryland|
|Liu, Ge - George|
|TAYLOR, ROBERT - University Of Maryland|
|SONG, JIUZHOU - University Of Maryland|
Submitted to: Journal of Animal Science and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2018
Publication Date: 9/13/2018
Publication URL: http://handle.nal.usda.gov/10113/6135302
Citation: Xu, L., He, Y., Ding, Y., Liu, G., Zhang, H., Cheng, H.H., Taylor, R.L., Song, J. 2018. Genetic assessment of inbred chicken lines indicates genomic signatures of resistance to Marek’s disease. Journal of Animal Science and Biotechnology. 9:65. https://doi.org/10.1186/s40104-018-0281-x.
Interpretive Summary: The persistent threat of Marek’s disease (MD) to the poultry industry is real and serious. Although since the 1970’s, MD has been successfully controlled by intensive use of MD vaccines, but the MD virus (MDV), which causes MD in chickens, continuously evolve with escalated virulence worldwide. Therefore, advancement in understanding genetic resistance to MD is the key, which will empower development of alternative strategies to augment current control measure. This study explored an important epigenetic factor, known as histone modification, in thymus tissues of two lines of chickens differed in resistance to MD. Genome-wide variability was observed post MDV challenge between the two lines of chickens. The findings suggested MD resistance is not only attributable to genetic background, but also to epigenetic background of the chickens. The findings also paved the way to further explore the functionality of histones with specific modifications induced by MDV challenge in tumor formation and progression.
Technical Abstract: Background Marek’s disease (MD) is a highly contagious pathogenic and oncogenic disease primarily affecting chickens. However, the mechanisms of genetic resistance for MD are complex and not fully understood. MD-resistant line 63 and MD-susceptible line 72 are two highly inbred progenitor lines of White Leghorn. Recombinant Congenic Strains (RCS) were developed from these two lines, which show varied susceptibility to MD. Results We investigated genetic structure and genomic signatures across the genome, including the line 63 and line 72, six RCSs, and two reciprocally crossed flocks between the lines 63 and 72 (F1 63'×'72 and F1 72'×'63) using Affymetrix® Axiom® HD 600 K genotyping array. We observed 18 chickens from RCS lines were specifically clustered into resistance sub-groups distributed around line 63. Additionally, homozygosity analysis was employed to explore potential genetic components related to MD resistance, while runs of homozygosity (ROH) are regions of the genome where the identical haplotypes are inherited from each parent. We found several genes including SIK, SOX1, LIG4, SIK1 and TNFSF13B were contained in ROH region identified in resistant group (line 63 and RCS), and these genes have been reported that are contribute to immunology and survival. Based on FST based population differential analysis, we also identified important genes related to cell death and anti-apoptosis, including AKT1, API5, CDH13, CFDP and USP15, which could be involved in divergent selection during inbreeding process. Conclusions Our findings offer valuable insights for understanding the genetic mechanism of resistance to MD and the identified genes could be considered as candidate biomarkers in further evaluation.