The first principles of heredity; with 75 illustrations and diagrms . ME12 Eiz Fig. 28.—Maturation of Parthenogenetic Ovum. {From Weismann, The Evolution Theory.) Uei, primitive ovum with four chromosomes ; MEiz, mother egg-cell with eight chromosomes; Eiz, formation of one polarbody (Rk^). chromosomes each. But now a second division is neces-sary, in order to reduce the number of chromosomes stillfurther to half the original number of the primitive ovum,which had four chromosomes. This takes place in thesame manner as just described for the formation of the firstpolar body. The remaining chro
The first principles of heredity; with 75 illustrations and diagrms . ME12 Eiz Fig. 28.—Maturation of Parthenogenetic Ovum. {From Weismann, The Evolution Theory.) Uei, primitive ovum with four chromosomes ; MEiz, mother egg-cell with eight chromosomes; Eiz, formation of one polarbody (Rk^). chromosomes each. But now a second division is neces-sary, in order to reduce the number of chromosomes stillfurther to half the original number of the primitive ovum,which had four chromosomes. This takes place in thesame manner as just described for the formation of the firstpolar body. The remaining chromosomes of the ovumdivide again, two now remaining finally in the ovum, andtwo forming a new polar body. As the first polar bodyalso has meanwhile divided into two, each with twochromosomes, we have as the final product of maturationthe ovum with two chromosomes (being half of the original 40 THE FIRST PRINCIPLES OF HEREDITY number) ready for fertilization, and three polar bodies,each with two chromosomes. The polar bodies, so far asour present knowledge goes, se
Size: 1304px × 1917px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondo, bookyear1910
