Un ejemplo se muestra en rosas. El alelo para el color rojo es dominante sobre el alelo para el color blanco, pero las rosas heterocigotas, que tienen ambos alelos, son rosadas. Tenga en cuenta que esto es diferente de la codominancia, que es cuando ambos alelos se expresan al mismo tiempo. Co-dominio se produce cuando los dos alelos en un par heterocigotos son mutuamente dominante o recesivo, lo que significa que ambos se expresan juntos. Esto a menudo puede dejar el par indeterminado, con elementos de cada alelo se expresan en un estado sometido.
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Ileana G. Santos Jussara V. Toniolo Geraldo Medeiros-Neto. Congenital hypothyroidism CH , as seen in the neonatal period, is predominantly caused by defects in the organogenesis athyreosis, ectopic thyroid, thyroid hypoplasia or by specific defects in hormonogenesis dyshormonogenesis.
Central hypothyroidism is rare, being linked to specific transcription factors involved in the maturation of the hypothalamic-pituitary axis or by mutations in the TSH-beta gene. Dyshormonogenesis may be caused by mutation coding for thyroid proteins such as the TSH receptor, the sodium-iodide symporter NIS , the pendrin Pendred's syndrome , thyroid peroxidase TPO , thyroglobulin Tg , thyroid dehalogenase, the receptor for thyroid hormone TR-beta or thyroid transport proteins TBG, transthyretin.
Usually, most of these defective genes will induce a phenotype with goiter and variable degree of hypothyroidism that may be present in the neonatal period or will gradually develop during post-natal life.
Moreover, the genetic expression may be partial or total according to the specific mutation occurring in the involved genes. Keywords: Ectopic thyroid; Thyroid hypoplasia; Dyshormonogenesis; Mutations; Thyroid genes; Congenital hypothyroidism. Muito recentemente, Congdon e cols. O estudo de Vilain e cols. Nos achados de estudos moleculares descritos por Bakker e cols. No Brasil, Santos e cols. Recent insights in the pathogenesis of neonatal hypothyroidism.
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A nonsense mutation causes human hereditary congenital goiter with preferential production of a nt thyroglobulin RNA messenger. Congenital goiter with hypothiroidism caused by a 5' spice mutation in the thyroglobulin gene. Genomic organization of the human thyroglobulin gene: the complete intron-exon structure. Eur J Endocrinol ;
Dominancia incompleta: Definición y ejemplo
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