College of Agriculture & Natural Resources

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    A WIDE SCALE INVESTIGATION INTO LNCRNA IN BOS TAURUS
    (2023) Marceau, Alexis; Ma, Li; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Although the history of genetic research has focused on genes and gene products, there is an interesting emerging subclass of genetic elements: long noncoding RNAs (lncRNAs). These are portions of the genome that are longer than 200 base pairs in length and are transcribed from DNA to RNA but do not yield a protein. The function of lncRNA is wide reaching and difficult to define; however, they are predominantly linked to the regulation of gene expression. This is done via transcriptional control, translation control, pre- and post- transcriptional and translational control, epigenetic modifications, RNA processing,as well as other methods. In this dissertation, multiple Bos taurus tissues across various life conditions were investigated in order to identify lncRNA and to begin making predictions about the role and function of identified transcripts. First, lncRNA were identified and analyzed in Bos taurus rumen tissue in pre-weaning and post-weaning cattle. lncRNA were implicated in the weaning process and demonstrated enrichment in complex traits, indicating the continued impact rumen-associated lncRNA have on dairy cattle. Following this study, mammary tissues from dry and lactating cattle were used for lncRNA analysis, in relation to the lacta-tion processes. This study revealed both the presence and impact of mammary lncRNA, and identified lncRNA associated with genes and biological processes that are strongly linked to lactation and mammary tissue function. Subsequently, immune system related tissues were analyzed for lncRNA and their roles. This investigation demonstrated lncRNA to be present in all investigated tissues, including transcripts being repeatedly present. Further analysis into identified lncRNA associated transcripts with genes and functions that are crucial to immune response. Finally, a tutorial was created to make lncRNA identification research more easily accessible to future researchers. The findings and creations of this dissertation increase the knowledge base of lncRNA and their role, allowing for further research endeavors and improvements in Bos taurus husbandry.
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    Investigation of rumen long noncoding RNA before and after weaning in cattle
    (Springer Nature, 2022-07-20) Marceau, Alexis; Gao, Yahui; Baldwin VI, Ransom L.; Li, Cong-jun; Jiang, Jicai; Liu, George E.; Ma, Li
    This study aimed to identify long non-coding RNA (lncRNA) from the rumen tissue in dairy cattle, explore their features including expression and conservation levels, and reveal potential links between lncRNA and complex traits that may indicate important functional impacts of rumen lncRNA during the transition to the weaning period. A total of six cattle rumen samples were taken with three replicates from before and after weaning periods, respectively. Total RNAs were extracted and sequenced with lncRNA discovered based on size, coding potential, sequence homology, and known protein domains. As a result, 404 and 234 rumen lncRNAs were identified before and after weaning, respectively. However, only nine of them were shared under two conditions, with 395 lncRNAs found only in pre-weaning tissues and 225 only in post-weaning samples. Interestingly, none of the nine common lncRNAs were differentially expressed between the two weaning conditions. LncRNA averaged shorter length, lower expression, and lower conservation scores than the genome overall, which is consistent with general lncRNA characteristics. By integrating rumen lncRNA before and after weaning with large-scale GWAS results in cattle, we reported significant enrichment of both pre- and after-weaning lncRNA with traits of economic importance including production, reproduction, health, and body conformation phenotypes. The majority of rumen lncRNAs are uniquely expressed in one of the two weaning conditions, indicating a functional role of lncRNA in rumen development and transition of weaning. Notably, both pre- and post-weaning lncRNA showed significant enrichment with a variety of complex traits in dairy cattle, suggesting the importance of rumen lncRNA for cattle performance in the adult stage. These relationships should be further investigated to better understand the specific roles lncRNAs are playing in rumen development and cow performance.