The 70 kilodalton heat shock proteins (Hsp70) are highly conserved molecular chaperones which have a crucial role in the stress response of the cell. In mammals, the Hsp70 proteins are encoded by a cluster of three genes: HSPA1A, HSPA1B and HSPA1L. In bovines, this cluster is located on chromosome 23 downstream of the major histocompatibility complex (BoLA). We detected inconsistencies in the location of markers on the Hsp70 genes reported in the literature that pointed to a potential deletion in the bovine reference genome UMD 3.1.1. An in silico analysis of the bovine genomic region of the Hsp70 cluster, using available information from public databases, confirmed the existence of a deletion of 11.1-kb spanning the HSPA1B gene and the intergenic region between HSPA1B and HSPA1A. Although we originally considered this an assembly error, it is most likely a particular condition of L1 Dominette 01449, the cow sequenced in the Bovine Genome Project. Moreover, we suggest a new classification of bovine Hsp70 sequences reported in NCBI and a reassignment of the location of SNPs from dbSNP that map to the deletion on BTA23. We also compared the location of selected transcription factor binding sites on the promoters of HSPA1A and HSPA1B. The results generated in the present work could be helpful to refine the reference genome of an important livestock species and also to understand the role and the regulation of the bovine Hsp70 genes.

No abstract

No abstract

Dynorphin A is an endogenous opioid peptide that is part of the KNDy system in the hypothalamus of mammals. This peptide acts as an inhibitor of the GnRH pulse generation, thus regulating the onset of puberty and reproductive cycles. The PDYN gene encodes the propeptide Prodynorphin, the precursor of Dynorphin A. Despite its physiological relevance, PDYN has not emerged as a candidate gene associated with puberty in genomic association studies conducted in cattle. The present work aimed to search for signatures of selection on the PDYN gene among cattle breeds. To this, the whole genome sequences from 57 samples of ten cattle breeds were used. The samples were grouped based on breed selection history and their productive differences, particularly in terms of sexual precocity. The population structure was analyzed using Principal Component Analyses. To evidence recent selection processes, neutrality tests, such as Tajima’s D and Fu & Li’s F* and D* were performed in defined functional regions of PDYN. The putative promoter of PDYN showed a population structure that is in agreement with the criteria considered to make the groups. In that region, neutrality tests were consistently negative and resulted in statistically significant for the dairy breeds. Also, these breeds exhibited less variability in the haplotype analyses than the others. The results presented here suggest that regulatory regions of PDYN could be under positive selection, particularly in dairy breeds. Key words: reproduction; KNDy neurons; Dynorphin; signatures of selection.