01964nas a2200145 4500008004100000022001400041245019300055210006900248260001600317520137800333100001801711700002301729700001401752856005201766 2017 eng d a1678-437500aPolyploidy as a chromosomal component of stochastic noise: variable scalar multiples of the diploid chromosome complement in the invertebrate species Girardia schubarti from Brazil.0 aPolyploidy as a chromosomal component of stochastic noise variab c2017 Jun 123 a

Chromosome stoichiometry, a form of genetic plasticity, specifically refers to variation in the standard diploid genomic composition of an individual or species. In the present work, freshwater planarians (Girardia schubarti) were analyzed to recognize variations in chromosomal stoichiometry especially of complete ploidal change between specimens, within specimens and between cells within specimens and any relations they might have with selected components of phenotypic plasticity. Homoploid polyploids for the group reached rational scalar multiples (e.g. tetraploids) or irrational scalar multiples (e.g. triploids). Karyotypic mosaics emerged where individual cells presented polyploid multiples in arithmetic and geometric progressions. Ploidal multiplicity, a chromosomal component of stochastic noise, had positive phenotypic effects (increased dimensions) on morphologic criteria of body length, body width and dorsal surface reflecting a significant genotypic plasticity (GP) and robust phenotypic plasticity (PP). Variable but significant association of genotypic plasticity with robust phenotypic variance suggests kinetics of phenotypic homeostasis that is species-specific permitting phenotypic adaptability to environmental variables by means of GP. That association is diminished, deactivated or lost in more advanced and more complex organisms.

1 aBenya, E, G F1 aLeal-Zanchet, A, M1 aHauser, J uhttps://continenticola.myspecies.info/node/174701216nas a2200169 4500008004100000022001400041245010200055210006900157260002000226300000800246490000700254520067600261100002600937700001600963700001500979856005200994 2004 eng d a1519-698400aMorphometry of the eyes in regenerant of genus Dugesia (Platyhelminthes, Turbellaria, Dugesiidae)0 aMorphometry of the eyes in regenerant of genus Dugesia Platyhelm aBrazilc02/2004 a1-90 v643 a

The photodocumentation technique was used weekly to observe until the end of the regenerative process of eyes in three species of Dugesia. Morphometric data based on the measurement of 96 samples of the species: Dugesia tigrina, D. schubarti, and D. anderlani were analyzed. A comparative analysis was made through graphic representation of statistical parameters of the following morphometric characters: the length of the transversal and longitudinal axes of the macula alba, pigment spot, and ocular opening. An interesting feature appeared in D. schubarti: the average of ocular opening during the regenerative process is bigger than in the original samples.

1 ade Campos-Velho, N, M1 aLopes, K, A1 aHauser, J. uhttps://continenticola.myspecies.info/node/128301513nas a2200193 4500008004100000022001400041245014200055210006900197260001200266300001200278490000700290520082100297100001401118700002901132700001901161700001501180700001701195856010701212 2007 eng d a1519-698400aChromosome polymorphism and complements in populations of Girardia species (Platyhelminthes, Tricladida, Paludicola) from Southern Brazil0 aChromosome polymorphism and complements in populations of Girard c12/2007 a951-9550 v673 a

The karyotypes of four species of freshwater triclads of the genus Girardia (Platyhelminthes), i.e. G. schubarti, G. tigrina, G. anderlani, and G. biapertura, from populations of different localities of the Rio Grande do Sul State, in southern Brazil, were analyzed. The karyotype of G. biapertura is presented for the first time. Three basic complements of 4, 8, and 9 chromosomes were found. Diploids, triploids, or mixoploids (2n/3n) specimens were frequently detected in these populations. The basic chromosomal complement of n = 9 was verified in two different species (G. biapertura and G. anderlani), presenting a large acrocentric chromosome which is rare in the family Dugesiidae. An intra and interspecific chromosomal variability was also detected and its evolutionary implications are discussed.

1 aBenya, E.1 aLeal-Zanchet, Ana, Maria1 aSantos, W., H.1 aHauser, J.1 aErdtmann, B. uhttp://www.scielo.br/scielo.php?script=sci_abstract&pid=S1519-69842007000500021&lng=en&nrm=iso&tlng=en