Sex-linked Inheritance in Drosophila

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Carnegie Institution of Washington, 1916 - Science - 87 pages
 

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Page 84 - ... the genes as linear. Surely this same data could legitimately be used in testing the hypothesis that the arrangement is non-linear. Moreover the Table 65 is, so far as I know, the only table in which the authors have ever given a comprehensive summary of their data. At the head of the table, they say "In Table 65 all data so far secured upon the sex-linked characters are summarized.
Page 14 - So far as we can see, there is no reason to suppose that the mutations which can be described as superf1cial are disproportionally more likely to occur than others.
Page 14 - Whatever the nature of the lethals' action, it can be shown that from among the offspring obtained from certain stocks expected classes are missing, and the absence of these classes can be accounted for on the assumption that there are present mutant factors that follow the Mendelian rule of segregation and which show normal linkage to other factors, but whose only recognizable difference from the normal is the death of those individuals which receive them.
Page 20 - ... such a color blind male (or any color blind male in fact) is mated with a female having this origin, half of the daughters will be color blind, half normal; half of the sons will be color blind, half will be normal. In other words the color blind grandmother transmits her defect to all of her sons, and to half of her granddaughters and to half of her grandsons. The inheritance of the chromosomes and of the defect is strictly parallel in this case also, as seen in the diagram (fig. 3). In the...
Page 9 - XX female must be due to an aberrant reduction division at which the two X chromosomes fail to disjoin from each other. In consequence both remain in the egg or both pass into the polar body.
Page 9 - Ordinarily all the sons and none of the daughters show the recessive sex-linked characters of the mother when the father carries the dominant allelomorph.
Page 9 - But that the Y does play some positive role is proved by the fact that all the XO males have been found to be absolutely sterile.
Page 24 - The system of symbols used in the diagrams and table headings is as follows: The...
Page 6 - Here, over a hundred characters that have been investigated as to their linkage relations are found to fall into four groups, the members of each group being linked, in the sense that they tend to be transmitted to the gametes in the same combinations in which they entered from the parents.
Page 7 - In the case of non-disjunction, to be given later, there is direct experimental evidence of such a nature that there can no longer be any doubt that the X chromosomes are the carriers of certain gens that we speak of as sex-linked.

About the author (1916)

A pioneer of genetics research in the first half of the twentieth century, Thomas Morgan won the Nobel Prize in 1933 for research that he had begun in 1910 with the fruit fly (Drosophila melanogaster). Reaching sexual maturity 12 to 14 hours after birth, the fruit fly had a number of heritable traits, primarily variations of wing shape and eye color, as well as large chromosomes easily visible under the microscopes of the time. The results of the experiments conducted in "The Fly Room," Morgan's laboratory at Columbia University, showed that two apparently different explanations of heredity, the chromosome theory (which identified the chromosomes of the cell nuclei as agents of heredity) and the Mendelian laws of inheritance were closely related. Morgan's contributions to genetics included the ideas that Gregor Mendel's factors or determinants of characteristics (now called genes) were grouped together on chromosomes, that some characteristics are sex-linked, and that the position of genes on chromosomes can be mapped.

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