This study aimed to exploring the intra-species distribution of genetic characters that favor the persistence in the gastrointestinal tract (GIT) and host interaction of bacteria belonging to the species Lacticaseibacillus genus. These bacterial species comprise commercial probiotics with the widest use among consumers and strains naturally occurring in GIT and in fermented food. Since little is known on the distribution of genetic traits for adhesion capacity, polysaccharide production, biofilm formation, utilization of substrates critically important for survival in GIT, that influence probiotic characteristics, a list of genetic determinants involved in such functions was created by a search for specific genes involved in the above aspects in the genome the extensively characterized probiotic L. rhamnosus GG. The presence/absence and variability of each gene in other Lacticaseibacillus spp. genomes was assessed by alignment with the publicly available fully annotated genome sequences. Eighty-two gene loci were compared, and 49 of these were found to be absent in some genomes in a species or strain-specific mode. A set of genes was found to be conserved, indicating that all strains of the genus may exert some probiotic effects. Among the variable loci a taurine utilization operon and a α-L-fucosidase were examined for presence/absence in 26 strains isolated from infant feces by PCR based tests. Results were variable among the isolates, though their common origin indicated the capacity to survive in the intestinal niche. This study indicated that the capacity to exert probiotic actions of Lacticaseibacillus spp. depends on a conserved set of genes and is enhanced by variable genetic factors whose role is only in part elucidated. The selection of strains of the most promising probiotic candidates to be used in food is feasible by analyzing presence/absence of a set of variable traits.