When there are several male pronuclei the segmentation is irregular and the resulting larva a monstrosity.
Fusion of male and female pronuclei to form the first segmentation nucleus.
Each spermatozoon forms a separate pronucleus with a surrounding sun; and several male pronuclei usually fuse with the female pronucleus.
While the two pronuclei are approaching one another the protoplasm of the egg exhibits amoeboid movements.
The product of the fusion of the two pronuclei forms the first segmentation nucleus (fig.
The actual fusion does not take place till after the pronuclei have been in contact for some time.
Each spermatozoon forms a separate pronucleus with a surrounding star; and several male pronucleiusually fuse with the female pronucleus.
In the mouse the subsequent events are as follow:--Both pronuclei assume the resting form, the chromatin being distributed over the nuclear network, and the nuclei come to lie side by side in the centre of the egg.
The fusion of the two pronuclei is sometimes effected in a manner slightly different from that described for the mouse.
If than one spermatozoon enters, a corresponding number of male pronuclei are formed, and the subsequent development, if it takes place at all, is abnormal and soon ceases.
There appears, however, to be some variation in this respect: cases have been observed in the mouse in which fusion of the pronuclei occurs before the separation of the chromosomes.
Biologie, 4) of the reduction of the number of chromosomes in the nucleus of both male and female gametes, and of the fact that the male and female pronuclei contribute the same number of chromosomes to the zygote-nucleus.
In Echinus, for instance, the two pronuclei fuse, and the spindle and chromosomes are formed from the zygote nucleus, whereas in the mouse the two pronuclei retain their distinctness during the formation of the chromosomes.
Giard suggests that in some cases of apparently normal fertilization one of the pronuclei may degenerate, the resultant embryo being the product of one pronucleus only.
The pronuclei have come into contact, and the spindle-system is now arranged across their common axis.
The second polar body has just been extruded; both male and female pronuclei contain two chromatin particles; those of the male pronucleus are becoming transformed into a skein.
The chromatin in both pronucleinow forms into a skein.
The conjugation of the pronuclei is apparently complete in VII.
Formation and conjugation of the pronuclei in Ascaris megalocephala.
The V-shaped chromatin filaments are now quite distinct: the male and female pronuclei are in close contact.
We do not know how long after insemination the pronuclei unite, but the proposition here is that as soon as they unite the human soul enters.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "pronuclei" in a variety of sentences. We hope that you will now be able to make sentences using this word.
