单词 | robertsonian |
释义 | Robertsonianadj. Genetics. Involving or relating to the formation of a metacentric chromosome from two heterologous acrocentric chromosomes by the fusion of their centromeres with the loss of the short arm of each parent chromosome. ΘΚΠ the world > life > biology > biological processes > genetic activity > genetic components > [adjective] > chromosome > formation of Robertsonian1949 1949 Evolution 3 380/1 The first type of study has led Matthey to attach much importance to transpositions of whole chromosome arms in evolution, i.e. structural changes whereby two rod-shaped chromosomes are replaced by one V or vice-versa. He calls such evolutionary changes ‘Robertsonian’ after the American cytologist, W. R. B. Robertson,..who emphasized their importance in the Orthoptera. 1954 M. J. D. White Animal Cytol. & Evol. (ed. 2) x. 192 In certain groups such as the Acrididae, ‘Robertsonian’ rearrangements or whole-arm transpositions account for a large part of the obvious differences in caryotypes. 1955 Nature 2 Apr. 601/1 The wide variation in the mitotic numbers must be attributed to Robertsonian changes. 1973 Nature 3 Aug. 262/1 The most common chromosomal changes seen in vertebrate evolution are Robertsonian fusions which create one metacentric from two acrocentrics. 2007 Sacramento (Calif.) Bee (Nexis) 31 Aug. j1 She has a genetic abnormality called Robertsonian translocation, and she knew there was a small chance she could have a baby with Down syndrome. This entry has been updated (OED Third Edition, June 2010; most recently modified version published online March 2022). < adj.1949 |
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