Whole-genome duplication and hemoglobin differentiation traits between allopatric populations of Brazilian Odontophrynus americanus species complex (Amphibia, Anura)

Abstract

Two allopatric populations of Brazilian diploid and tetraploid Odontophrynus americanus species complex, both from São Paulo state, had their blood hemoglobin biochemically analyzed. In addition, these specimens were cytogenetically characterized. Biochemical characterization of hemoglobin expression showed a distinct banding pattern between the allopatric specimens. Besides this, two distinct phenotypes, not linked to ploidy, sex, or age, were observed in adult animals of both populations. Phenotype A exhibits dark-colored body with small papillae, ogival-shaped jaw with reduced interpupillary distance and shorter hind limbs. Phenotype B shows yellowish-colored body with larger papillae, arch-shaped jaw with broader interpupillary distance and longer hind limbs. Intermediate phenotypes were also found. Considering the geographical isolation of both populations, differences in chromosomal secondary constrictions and distinct hemoglobins banding patterns, these data indicate that 2n and 4n populations represent cryptic species in the O. americanus species complex. The observed phenotypic diversity can be interpreted as population genetic variability. Eventually future data may indicate a probable beginning of speciation in these Brazilian frogs. Such inter- and intrapopulational differentiation/speciation process indicates that O. americanus species complex taxonomy deserves further evaluation by genomics and metabarcoding communities, also considering the pattern of hemoglobin expression, in South American frogs.

Research Article Evolution, Epigenetic inheritance, Development – a diplo/tetraploid model for Anura evolution

“…This hypothesis was further supported by data on erythropoiesis and the transcription of DNA coding for hemoglobin in 2n and 4n O. americanus, which revealed that the 4n cells have only 30% more hemoglobin and 25-30% more ribosomes that the 2n cells (Cianciarullo et al, 2000). Further studies on hemoglobin traits between allopatric populations of O. americanus 4n showed differences related to the process of diversification (Cianciarullo et al, 2019) Electron microscope studies showed that there are lower number of nuclear pore complexes (NPC) in the 4n with changes in the transport of products to the cytoplasm (Maul et al, 1980). Also, description by electron microscopy of complex aggregates of neighboring NPC in the 4n species may be related to a lower metabolic activity (Beçak and Fukuda-Pizzocaro, 2007).…”

Speciation Routes of Anurans

“…f. that the hemoglobin patterns of allopatric populations of Brazilian 2n and 4n O. americanus indicate that speciation does not require geographic barrier [61];…”

A new species of Odontophrynus (Anura, Odontophrynidae) from the southern portion of the Mantiqueira mountains

“…Herein lays the importance of combining multiple evidences of diagnostic traits. This is especially true for the genus Odontophrynus, for which there are several cryptic species (e.g., Rosset et al 2006Rosset et al , 2021Cianciarullo et al 2019), and lack of genetic, acoustic, and larval data for several populations (see Rocha et al 2017;Martino et al 2019;Rosset et al 2021).…”