Quantaux nice search Herbst OG-OD on causes this variability, we'll talk later we will discuss now the study of a series of highly interesting intersections where those bastards always have pure maternal traits, so they are any more hybrids.
This is Baltzer we need all our knowledge on the point. While crossing Sphaerechinus Strongylocenlroius gives hybrids, reciprocal cross Strongylocentroius Sphaerechinus gives only plutei S type pure rongylocenirolus. This is already done quite interesting cross between two species that did not even result ant knew that one of them is independent of maternal paternal Idu. exactly 'the same, moreover, between Spaerechinus Echinus giving hybrids, while Echinus Sphaerechinus gives plutei like pure Echinus. But the cytological study these results in combination shows more curious facts yet. I will describe it passes through the intersection Sphaerechinus Slrongylocentrotus it was earlier. But here is how fertilization of the egg by sperm Slrongylocentrotus Sphaerechinus penetrates celurci in ovular protoplasm takes the form of help with a thesis statement for a research paper a pronucleus Maie, just as in opposite case even copulation merging the pronuclei, then first CARJ ocinèse prepares medical residency personal statement writing services equatorial plate contains chromosomes from mother from father.
As each of these chromosomes cl e longitudinally, we need, at the end of mitosis, two daughter nuclei This fact is also not new. The different results obtained in horse crossing Q. donkey mule hinny the reverse is known example Readers unfamiliar with the cytology work may resent this little dissertation topics grammatical expression.
In reality, this is a short time-honored saying the nuclei of the daughter cells.
each containing chromosomes also. But they never contain more attent examines ement, oif maternal chromosomes found only paternal they have therefore gone to the first mitosis segmentation study shows they remain rear reconstitution time of the nuclei-girls, which they are excluded, rejected in protoplasm, where they now play no role.
This writing service personal statement is called V Baltzer elimination of paternal chromosomes.
regained process in several other crossings Eihinus SpJiaerechinus Arbacia SpJiaerechinus, A rbacia Strong i locentrolics and Ay hacia Echinus These are always paternal chromosomes are eliminated so the maternal chromosomes in cross Strongylocentrctus Arbacia perhaps in combination Echinus Q Arbacia no disposal chromosones paternal product, less in typical cases during first part development.
But during gastrulation, the cores are pathological appearance expel a certain amount chroma tine.
Most larvae die during this crisis so few surv ent sometime then see that their cores have become read little more than likely contain native chromatin. foreign chromatin introduced into egg is sometimes immediate, sometimes it produces that when the egg undergo its first lifïéreuciatioiis. The explanation each help with a thesis statement other remains unclear. The first idea that in mind is that of a toxic effect on a species cytoplasm sperm nucleus protoplasm spermaliques a foreign species. The result completely bound cross between Sphacrechinus Slrongylocenlrolus CF reverse combination makes this inconceivable theory. On the other hand, we will see more foreign sex cells even in origin, unite tolerate well pcMidant thesis editing extended far Development. A purely mechanical explanation is more tempting know that each species has its lylhme determined in succession in the evolution mitosis each particular glues it a closely related species can have rhythm ditrérent one back essential conditions for a mitosis normally ends is that gathered chromosomes Equatorial cl ent plate definite moment corresponding to optimum development of polar radiation. therefore may well arr st chromosomes of a species pace mitosique A, introduced in equatorial plate of a species r-RHYTHM B, do not arr ent cl er in time.