In all cases the results of the isolation of the first blastomeres seem to agree with the demonstrable structure of the unfertilized egg.
When the sperm is added while the eggs are in active parthenogenetic cell division the individual blastomeres into which a spermatozoon enters will also form a fertilization membrane, but such blastomeres perish very rapidly.
He isolated the first two blastomeres of the egg of Lanice, an Annelid.
These two blastomeres are somewhat different in size; from the larger one of the first two blastomeres, the segmented trunk of the worm originates.
If this idea is correct, the apparent power of "regulation" of the blastomeres should differ according to the degree of fluidity and the possibility of different layers separating, and this assumption is apparently supported by facts.
If we were to study the “selection” of the faculty of one of the isolated blastomeres of the egg of the sea-urchin to form a whole larva only of smaller size, the absurdities would increase.
With a hot needle he killed one of the first two blastomeres of the frog’s egg after the full accomplishment of its first cleavage, and then watched the development of the surviving cell.
We know already that each of the first two, or each of the first four, or three of the first four blastomerestogether may produce a whole organism.
The zoologist Chun had found even before Roux’s analytical studies, that isolated blastomeres of the ctenophore egg behave like parts of the whole and result in a half-organisation like the frog’s germ does.
He followed this up in the next year[493] by showing that whole embryos could be produced from one or more blastomeres isolated at the four-cell stage.
A number of years previously Chun had made the discovery that single blastomeres of the Ctenophore egg, isolated at the two-celled stage, gave half-embryos.
A year or two later Herlitzka[500] found that if the first two blastomeres of the newt's egg were separated by constriction, two normal embryos of rather more than half normal size were formed.
In a blastula showing complete segmentation the blastomeres of the upper hemisphere are the more finely subdivided.
Crampton by separating and isolating theblastomeres in the two-cell stage obtained a half embryo; and Zoja by isolating blastomeres of the medusae, Clytia and Laodice, got dwarfed larvae.
In these cases of injured and isolated blastomeres we have, it seems to me, a plausible theory for the etiology of single terata.
The blastomeres in the human ovum may perhaps be injured in part by toxins from the mother, or they may be defective through disease in the ovum or the spermatozoon.
Hertwig under which one of the two first blastomeres of this egg developed into a whole embryo of half size.
Driesch had already (1900) shown that any one of the first four blastomeres of a normally fertilized egg will, if isolated, develop normally.
Boveri found that in the case of the doubly fertilized egg the isolated "1/4" blastomeres develop very variously, a variability only to be accounted for by their varying chromosome equipment.
The fact that they are invariably of the same sex is a strong reason for believing that sex was already developed in the fertile ovum and consequently in the resulting blastomeres from that ovum.
It has been established experimentally in several kinds of animals that early cleavage blastomeres when isolated can each develop into a complete individual.
Up to a certain stage of development the blastomeres of the Medusa embryo are totipotent, or capable of developing into any part of the body.
Each of the two blastomeres contains all the materials potentially for the formation of the whole body, and these materials build up a whole body or a half body according to the grouping they take on.
We can artificially obtain double embryos of frogs by inverting the blastomeres in the two-cell stage.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "blastomeres" in a variety of sentences. We hope that you will now be able to make sentences using this word.
