Browsing by Subject "Chromosomes"

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    Symmetry applied to nuclear microanatomy: a review of gene function and cell differentiation
    (Murcia : F. Hernández, 2004) Bell, C.D.
    The purpose of this paper is to review current knowledge and understandings of gene control and cell differentiation, based upon an appreciation of a possible role that nuclear microanatomy and considerations of steric symmetry might play. Metaphase sister chromatids have identical base codes but show a mirror image symmetry of higher order coiling. Chromosomes in the interphase nucleus have spatially well defined domains and are anatomically distinct and ordered. Chromosomes are known to have interactions i.e. sex chromosome inactivation, PEV etc An hypothesis of gene activation is made based on steric interactions among chromosomes and between chromosomes and activating and repressor proteins. These interactions may be influenced by the handedness of higher order chromatid coiling, since homologues show mirror-image symmetrical coiling in metaphase, which might be retained to a certain degree in interphase. This may result in a binary switching of genes. All possible combinations of chromatids in the interphase nucleus, would be enabled by a differential segregation of homologous chromatids at mitosis. To conserve patterns of interchromatid interactions, there must be a programmed segregation of chromatids towards one of the two spindle pole attachments. This orientation might be effected by preferential attachment of microtubules to kinetochore attachment sites, by steric hindrance of the kinetochore by condensed chromatin which initially allows only unidirectional tubule attachment, or possibly by a tethering of interacting chromatids which would migrate en masse. An attempt to apply this hypothesis to some illustrative pathological conditions is made.
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    Tecnorituales del embarazo: cuerpos de mujer en el origen de la genética medica
    (Universidad de Murcia. Servicio de Publicaciones, 2017) Santesmases, María Jesús
    El objetivo de este artículo es mostrar la participación de las mujeres y de su descendencia en la construcción de la genética médica. Las mujeres y la infancia han sido el foco de atención de la genética desde que este espacio biomédico apareció en la clínica entre finales de la década de 1950 y principio de la de 1960. Esto fue así porque la agenda de la fertilidad ha guiado en buena parte los estudios y los razonamientos sobre la herencia de caracteres en la genética médica. Para desarrollar esta idea presentaré una historia de las imágenes de la genética durante ese periodo, narrativas visuales que transitan de los cuerpos humanos a las imágenes de sus cromosomas, para regresar a los cuerpos, e incluir a la genética medica y sus diagnósticos entre los derechos que la cultura de la reproducción han concedido a las mujeres en la era de la prensa fetal gráfica y la ecografía obstétrica.