31. A female with 47 chromosomes have normal phenotype. Her chromosome complements will be-
(1) 44 + XXY           (2) 44 + XXX
(3) 45 + xx             (4) 44+ XYY

Concept

Humans normally have 46 chromosomes: 44 autosomes + 2 sex chromosomes.
A phenotypically normal female with 47 chromosomes most often has trisomy X (47,XXX). Many 47,XXX women are clinically normal or have only mild, often unnoticed features.

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Option-wise explanation

1. 44 + XXY (47,XXY)

   • This is the classic Klinefelter syndrome karyotype, usually giving a male phenotype with small testes and infertility.

   • So it does not match a normal female.

2. 44 + XXX (47,XXX) – correct

   • Also called trisomy X.

   • Individuals are female and often have normal appearance and fertility; many are diagnosed only incidentally.

   • Fits “47 chromosomes” and “normal phenotype female.”

3. 45 + XX (47,XX+1 autosome)

   • This implies an extra autosome (total 45 autosomes + XX), which would be a serious autosomal trisomy (e.g., 47,XX,+21) and usually not phenotypically normal.

4. 44 + XYY (46,XYY)

   • This gives a male karyotype (XYY syndrome), not female.

Therefore, the chromosome complement of a phenotypically normal female with 47 chromosomes is 44 + XXX (option 2).