"Major clades" refers to large groups or branches in the evolutionary tree. It represents the significant divisions or categories in the classification of species based on their genetic relationship and common ancestry. Full definition
Relationships of Caryophyllales to other major clades of eudicots remain unclear. (eol.org)
This reveals a greater ecological diversity in an early mammaliaform clade at a more fundamental taxonomic level not only between major clades as previously thought. (science.sciencemag.org)
The study also revealed that the co-inheritance among major clades of T. gondii of large haploblocks enriched in clustered SPD genes shapes the population structure of this parasite and might determine host range, transmission and pathogenicity. (jcvi.org)