Of note, variation of copy number gain spanning the interval between 1.57 Mb and 2.99 Mb on bovine chromosome 21 has been found by the comparison of individual whole genome sequence data of Nellore with the B. taurus breeds Angus, Holstein and Hereford. As the Prader-Willi Syndrome is caused by loss of the paternal copy of the orthologous sequence in humans, and MAGEL2 is essential for proper hypothalamic control of growth and fertility, association of copy number variants with growth and reproductive traits seems to be a sensible hypothesis to be tested on this chromosome segment. The locus detected on chromosome 7 encompasses SH3RF2. Rubin et al. discovered a deletion removing all but the first exon of the orthologous chicken gene that is associated with body weight, and demonstrated that strong selection caused the deletion to reach fixation in a high growth lineage. Interestingly, using a mouse model of Prader-Willi syndrome, Stefan et al. found that loss of expression of the MAGEL2 region induces upregulation of SH3RF2 and its flanking genes TCERG1, LARS, RBM27 and GPR151. As both the MAGEL2 and the SH3RF2 regions were flagged in the present study, a trans-acting regulatory mechanism involving the loci on chromosomes 7 and 21 found here is likely to underlie SC variation. Hence, these signals are plausible candidates for weight and male fertility traits in Nellore cattle. Fortes et al. reported associations for IGF1 at 6 months and SC at 12 months in young Brahman bulls in an overlapping region around 25 Mb, which was previously shown to correlate with age of Brahman bulls when they achieve 26 cm of SC. This region has been well characterized in taurine cattle as harboring several human orthologues affecting stature and growth, especially PLAG1. The locus has also been found to be associated with birth weight in Nellore cattle, and suggested to shelter polymorphisms with pleiotropic effects on traits that correlate with body size. Furthermore, some first evidences for pleiotropism in body size and fertility traits in the PLAG1 region have been recently found in Brahman cattle. Although the human stature orthologues flanking 25 Mb are appealing candidates for SC, the chromosome 14 signal found here comprises a large segment spanning from 20.25 Mb to 35.85 Mb. This may be evidence that multiple genes and variants PI-103 msds within this region are involved. For instance, SNAI2 is located around 21.58 Mb and encodes for Slug, a Zinc-finger transcription factor that when mutated in mice produces males with testicular atrophy and marked decrease in seminiferous tubules sizes. Although these mice are able to copulate, their offspring are small. Also, Fortes et al. showed that ability to produce sperm at 18 months in Brahman bulls is not as significant around 25 Mb, and exhibits signals of association shifted towards the 35 Mb position instead. Another possible justification for a signal coming from such a large chromosome segment is a long range linkage disequilibrium persistency within the region.