R. Ruggles Gates

Bio: R. Ruggles Gates is an academic researcher from Marine Biological Laboratory. The author has contributed to research in topics: Ploidy & Oenothera. The author has an hindex of 16, co-authored 64 publications receiving 968 citations. Previous affiliations of R. Ruggles Gates include University of Cambridge.

Cytology and Genetics

Abstract: THE development of cytology in its relation to genetics is a chapter of more than usual interest in the history of biology. Cytology in the modern sense developed during the last quarter of the nineteenth century as a purely observational science. The general nature and behaviour of cells, nuclei and chromosomes were worked out during that period, although the cell theory, of course, originated much earlier. The rediscovery of Mendelism and the announcement of mutation at the turn of the present century marked a new epoch in biology, and soon gave abundant meaning to the observations regarding chromosomes which the cytologists had already accumulated. Henceforth cytology and the young science of genetics mutually influenced each other, and each derived increasing strength from the observations of the other. Introduction to Cytology. By Lester W. Sharp. (McGraw-Hill Publications in the Agricultural and Botanical Sciences.) Third edition. Pp. xiv ‘ 567. (New York and London: McGraw-Hill Book Co., Inc., 1934.) 30s. net.

A Study of Reduction in Oenothera rubrinervis

Abstract: In conclusion a brief summary of the facts and considerations here presented will be useful. 1. In Oenothera the heterotypic mitosis is a reduction division, separating whole chromosomes which lie successively on the spirem. The homotypic mitosis is an equation division, separating the longitudinal halves of the daughter chromosomes of the heterotypic mitosis. Whether an approximation of threads or a split in a single thread occurs in synapsis was not determined with certainty from the observations, but various considerations lead to the belief that in Oenothera the doubling is due to a split which closes up later, rather than to an approximation of separate spirems. 2. The conclusion that the method of reduction probably differs in different genera is based on two considerations: (1) the fact that in most of the recent accounts of synapsis and reduction in plants a side-by-side pairing of chromosomes from maternal and paternal spirems is described, while in Oenothera the members of a pair are arranged en...

Evolution and Genetics

Abstract: THIS little book originally appeared in the form of four lectures given at Princeton University in 1916. After three reprintings a new edition has been called for. The author has responded by revising the book and giving it a new title, breaking the contents up into thirteen chapters, including a new chapter (previously published elsewhere) on the non-inheritance of acquired characters, and another short chapter on human inheritance. It is an excellent discussion of evolutionary theory on the basis of the more recent discoveries in genetics and mutation. The case against the inheritance of acquired characters is very cogently stated. Evolution and Genetics. By Prof. Thomas Hunt Morgan. Pp. ix + 211. (Princeton: Princeton University Press; London: Oxford University Press, 1925.) 9s. net.

The Behavior of the Chromosomes in Oenothera lata x O. gigas

Abstract: 1. O. lata x O. gigas has 21 chromosomes in its somatic cells, 7 of maternal origin (O. lata) and 14 of paternal origin (O. gigas). In one individual the number was 20, owing probably to the absence of one chromosome from one of the germ cells which produced this individual. 2. These chromosomes segregate at the time of reduction, so that in individuals having 21 chromosomes half the germ cells receive 10 and half 11 chromosomes. In the individual having 20 chromosomes, 10 enter each germ cell. Occasionally one chromosome goes to the wrong pole of the spindle, so that in plants having 21 chromosomes a few germ cells are found having 9 or 12 chromosomes and in the plant with 20 chromosomes, occasional germ cells have 9 or 11 chromosomes. This irregularity in chromosome distribution accounts for the fact that different individuals in a race in some cases have different numbers of chromosomes. 3. The 10-11 segregation of chromosomes in the formation of the germ cells of this hybrid shows that there is not he...

A morphological distinction between neurones of the male and female, and the behaviour of the nucleolar satellite during accelerated nucleoprotein synthesis.

Abstract: Geneticists have long emphasized that ‘maleness’ and ‘femaleness’, so far as chromosome content is concerned, are projected from the fertilized ovum into the morphologically and functionally specialized somatic cells. It appears not to be generally known, however, that the sex of a somatic cell as highly differentiated as a neurone may be detected with no more elaborate equipment than a compound microscope following staining of the tissue by the routine Nissl method.

Arabidopsis is susceptible to infection by a downy mildew fungus.

Abstract: A population of Arabidopsis thaliana growing locally in a suburb of Zurich called Weiningen was observed to be infected with downy mildew. Plants were collected and the progress of infection was investigated in artificial inoculations in the laboratory. The plants proved to be highly susceptible, and pronounced intercellular mycelial growth, haustoria formation, conidiophore production, and sporulation of the causal organism Peronospora parasitica were all observed. The formation of oogonia, antheridia, and oospores also occurred. In contrast, Arabidopsis strain RLD was resistant to infection and none of the above structures was formed. The fungus was localized very soon after penetration of RLD leaf cells, which responded with a typical hypersensitive reaction. The differential interaction of an isolate of P. parasitica with two strains of Arabidopsis opens up the possibility of cloning resistance determinants from a host that is very amenable to genetic and molecular analysis.

A decade of transcription factor-mediated reprogramming to pluripotency

Abstract: This year marks the tenth anniversary of the generation of induced pluripotent stem cells (iPSCs) by transcription factor-mediated somatic cell reprogramming. Takahashi and Yamanaka portray the path towards this ground-breaking discovery and discuss how, since then, research has focused on understanding the mechanisms underlying iPSC generation and on translating such advances to the clinic.

Mitosis and the Physiology of Cell Division

Abstract: Publisher Summary The reproduction of biological systems may be referred to the reproduction of cells Subcellular entities such as viruses cannot maintain themselves indefinitely without parallel reproduction of the cells in which they live The asexual reproduction of organisms such as flatworms is limited by the production of new cells, and all cases of sexual reproduction imply the generation of new cells after the mixing of genetic material from the parent cells An evolutionary consequence of cellularity is implicit in the designation of multicellular organisms as higher organisms Single cells can develop a high level of variety and complexity of structure and function In the development of a multicellular organism, cell division, beginning with the egg, is the essential step toward differentiation If mitosis is a device for the distribution of sister genes to sister cells, the chromosomes may be viewed as a system in which the numerous genes are packaged into a small number of units Mitosis is accompanied by some changes in the physical state or texture of the cytoplasm, which have been assessed as viscosity changes