This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'Barr body is absent in female having – \nSelect and explain. \nA. 46 XX genome, B. 45 XO genome, C. 47 XXX, D. All of above', 'role': 'user'}, {'content': "Answer: B \nExplanation: Barr body (Sex - chromatin)\n\nIt is a densely staining inactivated condensed 'X' chromosome that is present in each somatic cells of the female.\nIt is found in the nucleus.\nIt is used as a test of genetic femaleness → it is possible to determine the genetic sex of an individual according as to whether there is a chromatin mass present on the inner surface of the nuclear membrane of cells with resting or intermittent nuclei. Remember the following fact and the question will seem very easy.\nChromatid body (Barr body or sex chromatin) is derived from one of the two X-chromosomes which becomes inactivated.\nThe number of Barr bodies is thus one less than the number of X-chromosomes.\n\nNote -\n\nBarr body is found in female But -\nKleinefelter syndrome is male with Barr body.\nTurner syndrome is female without Barr body.", 'role': 'assistant'}]