"truxillense" are phenotypically similar, but morphologically distinguishable. These syndrome subtypes are phenotypically similar despite arising from different gene abnormalities. Reciprocal heterozygotes have a genetically equivalent, but they are phenotypically nonequivalent. This usually involves identifying multidimensional regions that contain functionally and phenotypically homogeneous groups of cells. Evolutionarily traits that have disappeared phenotypically do not necessarily disappear from an organism's DNA. In other cases, mutations may be harmless or phenotypically unnoticeable. Individuals with this chromosomal arrangement have 45 chromosomes and are phenotypically normal. Variable expressivity refers to the degree in which a genotype is phenotypically expressed. Many common culturable laboratory strains are deep-frozen to preserve genetically and phenotypically stable, long-term stocks. The most common presentation of 45,X/46,XY karyotype is phenotypically normal male, next being genital ambiguity. Clusters of peaks inhabited by phenotypically similar populations can be viewed as higher taxonomic levels. Upon further study of the genus, "Ralstonia" was found to comprise two phenotypically distinct clusters. The phenotypically dominant organism is the individual in question in a test cross. Across its geographic range, this species varies greatly phenotypically. Tibetans are phenotypically diverse, and exhibit high-altitude adaptations.