South of the Po Valley in Italy, green frogs constitute a hybridogenetic system, represented by o... more South of the Po Valley in Italy, green frogs constitute a hybridogenetic system, represented by one parental species (Rana lessonae) and a hybrid form (R. esculenta). Lacking one parent (R. ridibunda), the hybrid is a reproductive parasite on the coexisting parent: progeny from matings between hybrids are inviable; the hybrid reproduces hybridogenetically by first eliminating the R. lessonae genome from the germ-line cells prior to meiosis, reduplicating the R. ridibunda set, and then transmitting the R. ridibunda genome hemiclonally to gametes. Hybridity is restored in each generation, since R. esculenta gametes are fertilised by gametes from R. lessonae. In order to ascertain whether there are any differences in susceptibility to environmental disturbances between the parental species and the hybrid form, the green frogs living in Lake Trasimeno (central Italy) were analysed. In the absence of reliable morphological systematic characteristics, hybrids and nonhybrids were distinguished by means of a species-specific centromeric satellite DNA, and the percentages of R. lessonae and R. esculenta specimens at each sampling station were calculated. The results indicate that the parental host is more susceptible to negative environmental factors, which could threaten the whole local hybridogenetic system.
South of the Po Valley in Italy, green frogs constitute a hybridogenetic system, represented by o... more South of the Po Valley in Italy, green frogs constitute a hybridogenetic system, represented by one parental species (Rana lessonae) and a hybrid form (R. esculenta). Lacking one parent (R. ridibunda), the hybrid is a reproductive parasite on the coexisting parent: progeny from matings between hybrids are inviable; the hybrid reproduces hybridogenetically by first eliminating the R. lessonae genome from the germ-line cells prior to meiosis, reduplicating the R. ridibunda set, and then transmitting the R. ridibunda genome hemiclonally to gametes. Hybridity is restored in each generation, since R. esculenta gametes are fertilised by gametes from R. lessonae. In order to ascertain whether there are any differences in susceptibility to environmental disturbances between the parental species and the hybrid form, the green frogs living in Lake Trasimeno (central Italy) were analysed. In the absence of reliable morphological systematic characteristics, hybrids and nonhybrids were distinguished by means of a species-specific centromeric satellite DNA, and the percentages of R. lessonae and R. esculenta specimens at each sampling station were calculated. The results indicate that the parental host is more susceptible to negative environmental factors, which could threaten the whole local hybridogenetic system.
STEFANIA BUCCI MATILDE RAGGHIANTI FRANCESCA GUERRINI VALENTINA CERRINI GIORGIO MANCINO Laboratori... more STEFANIA BUCCI MATILDE RAGGHIANTI FRANCESCA GUERRINI VALENTINA CERRINI GIORGIO MANCINO Laboratorio di Biología cellulare e dello Sviluppo, Dipartimento di Fisiología e Biochimica, Università di Pisa, via Carducci 13, I-56010 Ghezzano, Pisa (Italy)
South of the Po Valley in Italy, green frogs constitute a hybridogenetic system, represented by o... more South of the Po Valley in Italy, green frogs constitute a hybridogenetic system, represented by one parental species (Rana lessonae) and a hybrid form (R. esculenta). Lacking one parent (R. ridibunda), the hybrid is a reproductive parasite on the coexisting parent: progeny from matings between hybrids are inviable; the hybrid reproduces hybridogenetically by first eliminating the R. lessonae genome from the germ-line cells prior to meiosis, reduplicating the R. ridibunda set, and then transmitting the R. ridibunda genome hemiclonally to gametes. Hybridity is restored in each generation, since R. esculenta gametes are fertilised by gametes from R. lessonae. In order to ascertain whether there are any differences in susceptibility to environmental disturbances between the parental species and the hybrid form, the green frogs living in Lake Trasimeno (central Italy) were analysed. In the absence of reliable morphological systematic characteristics, hybrids and nonhybrids were distinguished by means of a species-specific centromeric satellite DNA, and the percentages of R. lessonae and R. esculenta specimens at each sampling station were calculated. The results indicate that the parental host is more susceptible to negative environmental factors, which could threaten the whole local hybridogenetic system.
South of the Po Valley in Italy, green frogs constitute a hybridogenetic system, represented by o... more South of the Po Valley in Italy, green frogs constitute a hybridogenetic system, represented by one parental species (Rana lessonae) and a hybrid form (R. esculenta). Lacking one parent (R. ridibunda), the hybrid is a reproductive parasite on the coexisting parent: progeny from matings between hybrids are inviable; the hybrid reproduces hybridogenetically by first eliminating the R. lessonae genome from the germ-line cells prior to meiosis, reduplicating the R. ridibunda set, and then transmitting the R. ridibunda genome hemiclonally to gametes. Hybridity is restored in each generation, since R. esculenta gametes are fertilised by gametes from R. lessonae. In order to ascertain whether there are any differences in susceptibility to environmental disturbances between the parental species and the hybrid form, the green frogs living in Lake Trasimeno (central Italy) were analysed. In the absence of reliable morphological systematic characteristics, hybrids and nonhybrids were distinguished by means of a species-specific centromeric satellite DNA, and the percentages of R. lessonae and R. esculenta specimens at each sampling station were calculated. The results indicate that the parental host is more susceptible to negative environmental factors, which could threaten the whole local hybridogenetic system.
STEFANIA BUCCI MATILDE RAGGHIANTI FRANCESCA GUERRINI VALENTINA CERRINI GIORGIO MANCINO Laboratori... more STEFANIA BUCCI MATILDE RAGGHIANTI FRANCESCA GUERRINI VALENTINA CERRINI GIORGIO MANCINO Laboratorio di Biología cellulare e dello Sviluppo, Dipartimento di Fisiología e Biochimica, Università di Pisa, via Carducci 13, I-56010 Ghezzano, Pisa (Italy)
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