Andrey Yurkov and his colleagues review how evolving species concepts have been applied to understand yeast diversity. Initially, a phenotypic species concept was utilized taking into consideration morphological aspects of colonies and cells, and growth profiles. Later the biological species concept was added, which applied data from mating experiments. Biophysical measurements of DNA similarity between isolates were an early measure that became more broadly applied with the advent of sequencing technology, leading to a sequence-based species concept using comparisons of parts of the ribosomal DNA. At present phylogenetic species concepts that employ sequence data of rDNA and other genes are universally applied in fungal taxonomy, including yeasts, because various studies revealed a relatively good correlation between the biological species concept and sequence divergence.
(excerpt from the publication)
For more information see
Boekhout, T., Catherine Aime, M., Begerow, D., Gabaldón, T., Heitman, J., Kemler, M., Khayhan, K., Lachance, M., Louis, E.J., Sun, S., Vu, D. & Yurkov, A. (2021) The evolving species concepts used for yeasts: from phenotypes and genomes to speciation networks. Fungal Diversity volume 109, pages 27–55 (2021)
https://doi.org/10.1007/s13225-021-00475-9