Heredity and sex . Fig. 31. — Dispermy and its effects in egg of sea urchin. (After Boveri.) Around these chromosomes a double system ofthreads develops with four poles. The chromosomesbecome unequally distributed on the four spindles thatdevelop. Each chromosome then divides, and half ofeach goes to the nearest pole. To some of the polesmany chromosomes may pass, to other poles fewer. THE MECHANISM OF SEX-DETERMINATION 57 In order to simplify the case let us imagine that eachsperm has only four chromosomes and the egg nucleusonly four. Let us represent these by the letters asshown in Fig. 32.
Heredity and sex . Fig. 31. — Dispermy and its effects in egg of sea urchin. (After Boveri.) Around these chromosomes a double system ofthreads develops with four poles. The chromosomesbecome unequally distributed on the four spindles thatdevelop. Each chromosome then divides, and half ofeach goes to the nearest pole. To some of the polesmany chromosomes may pass, to other poles fewer. THE MECHANISM OF SEX-DETERMINATION 57 In order to simplify the case let us imagine that eachsperm has only four chromosomes and the egg nucleusonly four. Let us represent these by the letters asshown in Fig. 32. Any one of the four cells that is
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Keywords: ., boo, bookcentury1900, bookdecade1910, booksubjectsex, bookyear1913
