Person: Puertas Gallego, María Jesús
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First Name
María Jesús
Last Name
Puertas Gallego
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Area
Genética
Identifiers
4 results
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Item One gene determines maize B chromosome accumulation by preferential fertilisation; another gene(s) determines their meiotic loss(Heredity, 2003) González Sánchez, Mónica; González-González, Esther; Molina, Francia; Chiavarino, Mauricio; Rosato, Carmen Luisa Marcela; Puertas Gallego, María JesúsGenotypes of high (Hm) and low (Lm) male B transmission rate (B-TR) were obtained. B-TR segregation in the F2 is reported, showing that the Hm and Lm lines differ in a single locus we call mBt (male B transmission), controlling B preferential fertilisation in maize. The egg cells control which one of the sperm nuclei is going to fertilise them, mBth egg cells being preferentially fertilised by the sperm nucleus carrying the supernumerary B chromosomes (Bs). It is hypothesised that the mBt gene is involved in the normal fertilisation of maize but the parasitic Bs take advantage of the mBth allele to increase their own transmission. Selection was also carried out when the Bs were transmitted on the female side (Hf and Lf lines). The F1 hybrids show that the gene(s) that we call fBt (female B transmission), controlling female B-TR, is located on the A chromosomes acting at diploid level, the fBtl allele(s) for low transmission being dominant. This allele causes the loss of Bs at meiosis, which is shown using a specific B molecular probe to determine B presence/absence in microspores of both lines and hybrids. Maize Bs are a nice example of intragenome conflict, because the mBt and fBt loci are a polymorphic system of attack and defence between A and B chromosomes.Item The parasitic effects of rye B chromosomes might be beneficial in the long term(Cytogenetic and Genome Research, 2004) González Sánchez, Mónica; M. Chiavarino; G. Jiménez; S. Manzanero; Rosato, Carmen Luisa Marcela; Puertas Gallego, María JesúsRye B chromosomes (Bs) have strong parasitic effects on fertility. B carrying plants are less fertile than 0B ones, whereas the Bs have no significant effects on plant vigour. On the other hand, it has been reported that B transmission is under genetic control in such a way that H line plants transmit the Bs at high frequency, whereas the Bs in the low B transmission rate line (L) fail to pair at metaphase I and are frequently lost. In the present work we analyse variables affecting vigour and fertility considering not only the number of Bs of each plant, but also its H or L status and the B number of its maternal parent. Our results show that the Bs not only decrease female fertility of the B carrier, but the fertility of its progeny, with the exception of 0B plants coming from a 4B mother, which are the most fertile. In this way B chromosomes can be considered as a selective factor. Pollen abortion was higher in B carriers, in the progeny of B carriers and in H plants, but 4B plants coming from B carrying mothers produce less aborted pollen, indicating that a high B number is more deleterious if it is transmitted in the pollen grains. A similar result was obtained for endosperm quality estimated as grain weight, because it is negatively influenced by the Bs in 4B plants coming from a 0B mother. H plants were always less fertile than L ones, indicating that alleles increasing the loss of Bs in the L line will be probably selected as a defence of the A genome against the invasive Bs of the H line. Flower number is not affected by the Bs.Item Mitotic microtubule development and histone H3 phosphorylation in the holocentric chromosomes of Rhynchospora tenuis (Cyperaceae)(Genetica, 2006) Guerra, Marcelo; Brasileiro-Vidal, Ana Christina; Arana Montes, María Del Pilar De; Puertas Gallego, María JesúsIn the present work we report the phosphorylation pattern of histone H3 and the development of microtubular structures using immunostaining techniques, in mitosis of Rhynchospora tenuis (2n = 4), a Cyperaceae with holocentric chromosomes. The main features of the holocentric chromosomes of R. tenuis coincide with those of other species namely: the absence of primary constriction in prometaphase and metaphase, and the parallel separation of sister chromatids at anaphase. Additionaly, we observed a highly conserved chromosome positioning at anaphase and early telophase sister nuclei. Four microtubule arrangements were distinguished during the root tip cell cycle. Interphase cells showed a cortical microtubule arrangement that progressively forms the characteristic pre-prophase band. At prometaphase the microtubules were homogeneously distributed around the nuclear envelope. Metaphase cells displayed the spindle arrangement with kinetochore microtubules attached throughout the entire chromosome extension. At anaphase kinetochoric microtubules become progressively shorter, whereas bundles of interzonal microtubules became increasingly broader and denser. At late telophase the microtubules were observed equatorially extended beyond the sister nuclei and reaching the cell wall. Immunolabelling with an antibody against phosphorylated histone H3 revealed the four chromosomes labelled throughout their entire extension at metaphase and anaphase. Apparently, the holocentric chromosomes of R. tenuis function as an extended centromeric region both in terms of cohesion and H3 phosphorylation.Item Is maize B chromosome preferential fertilization controlled by a single gene?(Heredity, 2001) Chiavarino, Mauricio; González Sánchez, Mónica; Poggio, Lidia; Puertas Gallego, María Jesús; Rosato, Carmen Luisa Marcela; Rosi, PabloIn previous work, genotypes for high and low B chromosome transmission rate were selected from a native race of maize. It was demonstrated that the B transmission is genetically controlled. The present work reports the fourth and fifth generations of selection and the F1 hybrids between the lines. The native B is characterized by a constant behaviour, with normal meiosis and nondisjunction in 100% of postmeiotic mitosis. It is concluded that genetic variation for B transmission between the selected lines is due to the preferential fertilization process. The F1 hybrids show intermediate B transmission rate between the lines. They are uniform, the variance of the selected character being one order of magnitude lower than that of the native population. In addition, 0B×2B and 2B×2B crosses were made to study the effect of the presence of B chromosomes in the female parent, resulting in non-significant differences. Several crosses were made both in Buenos Aires and in Madrid to compare the possible environmental effect, but significant differences were not found. Our results are consistent with the hypothesis of a single major gene controlling B transmission rate in maize, which acts in the egg cell at the haploid level during fertilization. It is also hypothesized that maize Bs use the normal maize fertilization process to promote their own transmission.