. The physical basis of heredity . y seem to be wrappedaround each other. Whether the threads are split lengthwise before theirunion can not be stated for all cases. It is certain thatno splitting has been seen in several animals, but in onecase {Ascaris) the threads have been found to be splitlengthwise before they conjugate. For a short time following the union of the threadsthey come in close contact with each other, and give theimpression of having fused into a single thread. Usuallybefore the nuclear wall breaks down to release the thickthreads, a split can be seen again extending through
. The physical basis of heredity . y seem to be wrappedaround each other. Whether the threads are split lengthwise before theirunion can not be stated for all cases. It is certain thatno splitting has been seen in several animals, but in onecase {Ascaris) the threads have been found to be splitlengthwise before they conjugate. For a short time following the union of the threadsthey come in close contact with each other, and give theimpression of having fused into a single thread. Usuallybefore the nuclear wall breaks down to release the thickthreads, a split can be seen again extending throughoutthe lengih of the threads. Not infrequently anotherlongitudinal split appears in each half resulting from the CROSSING OVER AND CHEOMOSOMES 101 first split, so that four parallel strands appear. It iscustomary to call the split, that is supposed to correspondto the line of union of the maternal and paternal chromo-some, the primary split or reductional split, and the splitthat corresponds to the longitudinal division within the.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectheredit, bookyear1919
