Contracture
发表于 2025-3-25 04:39:06
Conservation of the Original X and Homology of the X-linked Genes in Placental Mammalstal mammals gave the identical DNA value of 7.0 × 10. mg per diploid nucleus. It then became apparent that in this class extensive speciation from a common ancestor was accomplished almost exclusively by allelic mutation of individual gene loci with little or no change in the total number of gene loci.
Mosaic
发表于 2025-3-25 08:31:57
Conservation of the Original Z-Chromosome by Diverse Avian Species and Homology of the Z-linked Geneests that the Z-chromosome of this genome lineage is very ancient in its origin. It appears that the same primitive Z has persisted in its entirety not only in diverse avian species, but also in diverse ophidian species of today.
daredevil
发表于 2025-3-25 12:44:40
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腐烂
发表于 2025-3-25 18:26:29
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antecedence
发表于 2025-3-25 21:04:56
Evidence Indicating that the X and the Y or the Z and the W were Originally an Homologous Pair of Orthat the two were originally an homologous pair of ordinary chromosomes or autosomes. A broad review of the sex-determining mechanism of various vertebrates enables us to reconstruct, step-by-step, this process of sex chromosome differentiation.
Magisterial
发表于 2025-3-26 02:08:38
Differentiation of the Primitive Sex Elements at the Expense of the Y or W, and the Conservation of echanism does exist in lower vertebrates. However, the X and the Y or the Z and the W of fishes and amphibians are still in an initial stage of differentiation. The two opposing sex determiners are still almost entirely homologous to each other.
ligature
发表于 2025-3-26 07:21:06
Polyphyletic Evolution of Vertebratesment of the homogametic sex was conserved in its entirety. The differentiation was accomplished exclusively at the expense of the element which was elected to be the determiner of the heterogametic sex, the Y or the W.
在前面
发表于 2025-3-26 12:11:13
Conservation of the Original X and Homology of the X-linked Genes in Placental Mammals series of polyploidization of the original vertebrate genome occurred in ancient times. Once the chromosomal sex-determining mechanism was well established, the genome of that lineage was stabilized, and no further gene duplication by polyploidization was possible. Indeed, diverse species of placen
Silent-Ischemia
发表于 2025-3-26 14:03:06
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不透气
发表于 2025-3-26 20:05:28
The Basic Difference in Constitution between the Mammalian X and the Drosophila Xme a highly specialized male-determiner, having but one function namely to induce the indifferent embryonic gonad to develop as testis. The consequence of this specialization by the Y was that almost all of the original Mendelian genes which had been maintained by the X-chromosome, had to accommodat