RESUMEN
The review deals with features of sex determination in vertebrates. The mechanisms of sex determination are compared between fishes, amphibians, reptilians, birds, and mammals. We focus on structural and functional differences in the role of sex-determining genes in different vertebrates. Special attention is paid to the role of estrogens in sex determination in nonmammalian vertebrates.
Asunto(s)
Evolución Biológica , Estrógenos/genética , Cromosomas Sexuales/genética , Procesos de Determinación del Sexo , Animales , Aves/genética , Femenino , Peces/genética , Masculino , Mamíferos/genética , Reptiles/genéticaRESUMEN
'Holospora acuminata' infects micronuclei of Paramecium bursaria (Protozoa, Ciliophora), whereas 'Holospora curviuscula' infects the macronucleus in other clones of the same host species. Because these micro-organisms have not been cultivated, their description has been based only on some morphological properties and host and nuclear specificities. One16S rRNA gene sequence of 'H. curviuscula' is present in databases. The systematic position of the representative strain of 'H. curviuscula', strain MC-3, was determined in this study. Moreover, for the first time, two strains of 'H. acuminata', KBN10-1 and AC61-10, were investigated. Phylogenetic analysis indicated that all three strains belonged to the genus Holospora, family Holosporaceae, order Rickettsiales within the Alphaproteobacteria.