Sex determination in humans (XY)मनुष्य में लिंग निर्धारण (XY)
NCERT Fig 4.12 · Class 12 Biology · Chapter 4 · interactive diagram
Parts and their functions
- Mother: 44 + XX (माता: 44 + XX) — 22 pairs of autosomes + a pair of X chromosomes (homogametic).
- Father: 44 + XY (पिता: 44 + XY) — 22 pairs of autosomes + X and Y (heterogametic: makes two kinds of sperms).
- Ovum: 22 + X (अंडाणु: 22 + X) — Females make only one kind of ovum — every ovum carries an X.
- X-bearing sperm (50%) (X वाला शुक्राणु (50%)) — Half of all sperms carry X. X-sperm + ovum → XX → girl.
- Y-bearing sperm (50%) (Y वाला शुक्राणु (50%)) — Half of all sperms carry Y. Y-sperm + ovum → XY → boy.
- Girl: 44 + XX (लड़की: 44 + XX) — From an X-bearing sperm. Chance in every pregnancy: 50%.
- Boy: 44 + XY (लड़का: 44 + XY) — From a Y-bearing sperm. Chance in every pregnancy: 50%. The sperm (father) decides the sex.
Steps
- 1 · Parents: mother 44 + XX, father 44 + XY.
- 2 · Gametes: all ova X; sperms 50% X, 50% Y.
- 3 · Offspring: 50% girls (XX), 50% boys (XY).
Original diagram drawn by Simple Learning Hub, based on NCERT Fig 4.12. Report a mistake