From a search and objective evaluation of the currently available evidence, it is concluded that there is no unique factor able to predict male fertility, but several molecular factors are involved in sperm function and can potentially be considered as fertility markers.
The SNP with higher VI may be of interest for prediction of trait susceptibility (e.g. disease resistance, low fertility) at low marker density, candidate gene studies or gene expression studies.
The prediction method yielding the highest accuracy differed between traits: BayesBπ had the highest accuracy for protein yield, BayesCπ for mastitis and GBLUP for fertility when individual marker prediction was used.
Among other theories, academics have speculated that they may be territorial markers, fertility symbols, astronomical signs, or simply prehistoric doodles.
Several molecules were described to be differentially expressed between the high and low pregnancy rate groups, and also several molecules were described to be present or absent in one group, being considered, respectively, as potential fertility or infertility markers.
Although this status distribution would make it an optimal marker for fertility, it was only found in 1 animal from each group.
A significant number of these studies used resumption of menses as a surrogate marker for fertility and many reported a higher frequency of menstrual cycles in women who have received gonadotropin-releasing hormone analogs, but none has demonstrated a beneficial effect regarding fertility recovery.
As we point out in our article, in females the vast majority of clinical studies investigating gonadal protection by gonadotropin-releasing hormone analogs (GnRHa) during chemotherapy have been small, retrospective, and uncontrolled, and they have almost exclusively used resumption of menstruation as a surrogate marker for fertility.
Their putative differential expression in subfertile and fertile bulls could be used as markers for fertility, as already suggested for the αv6β3 integrin in humans [ 64].
