The Theory of the Gene |
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Page 35
... pole , and all the maternally derived to the other pole , the two resulting X or L ' ་ । FIG . 23 . Diagram to illustrate the random assortment of a pair of chromo- somes with respect to the X - chromosome . ( After Carothers . ) germ ...
... pole , and all the maternally derived to the other pole , the two resulting X or L ' ་ । FIG . 23 . Diagram to illustrate the random assortment of a pair of chromo- somes with respect to the X - chromosome . ( After Carothers . ) germ ...
Page 36
... poles . Now in these grasshoppers there is , in the male , an un- paired chromosome that is connected with sex determina- tion ( Fig . 23 ) . It passes at the maturation division to one pole or to the other . It serves as a land - mark ...
... poles . Now in these grasshoppers there is , in the male , an un- paired chromosome that is connected with sex determina- tion ( Fig . 23 ) . It passes at the maturation division to one pole or to the other . It serves as a land - mark ...
Page 55
... pole , or one X and the Y may mate , leaving a free X. Possibly all three may come together , and then separate so that two go to one pole of the maturation spindle and one to the opposite pole . The results are practically the same in ...
... pole , or one X and the Y may mate , leaving a free X. Possibly all three may come together , and then separate so that two go to one pole of the maturation spindle and one to the opposite pole . The results are practically the same in ...
Page 106
... pole , one to the other , as seen in d and e ( anaphase plates of c ) . ( After Wilson . ) species where the female has one or more chromosomes than the male , and there are other species where the in the eggs and sperms , are separate ...
... pole , one to the other , as seen in d and e ( anaphase plates of c ) . ( After Wilson . ) species where the female has one or more chromosomes than the male , and there are other species where the in the eggs and sperms , are separate ...
Page 110
... Lamarckiana that emerge from the synaptic tangle as stuck together somewhat irregularly and not strictly in side to side union . Later they move toward one or the other pole bringing about reduction . Cleland has. 110 THE THEORY OF THE ...
... Lamarckiana that emerge from the synaptic tangle as stuck together somewhat irregularly and not strictly in side to side union . Later they move toward one or the other pole bringing about reduction . Cleland has. 110 THE THEORY OF THE ...
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Common terms and phrases
14 chromosomes Abst.-Vererb allelomorph appear autosomes back-crossed Biol bivalents Blakeslee carried chro chromo chromosome groups chromosome numbers color conjugate cross crossing-over cytological Datura daughter develop dioecious diploid dominant double Drosophila melanogaster embryo Emmer Emmer group eyeless F₁ factors fertilized flies gametophyte gemini germ-cells give half haploid haploid number haplonts heredity hybrid individual interpretation intersexes Jour kinds linkage male and female mated maturation division mosomes moths mutant mutant characters mutant types normal nucleus number of chromosomes Oenothera offspring organs ovary pair of chromosomes parent parthenogenetic plants polar body pole pollen grains pollen mother cells polyploid present Proc produced protonema race ratio recessive genes relation secondary set of chromosomes sex-determination sex-linked sex-linked inheritance shown single chromosomes species sperm sperm-cells sporophyte stage studied sylvestris Tabacum takes place teosinte tetraploid theory tion triploid trisomic white eyes wild type wings X-chromosomes Zoöl
Popular passages
Page 25 - The theory states that ihe characters of the individual are referable to paired elements (genes) in the germinal material that are held together in a definite number of linkage groups; it states that the members of each pair of genes separate when the germ-cells mature in accordance with Mendel's first law, and in consequence each germ-cell comes to contain one set only; it states that the members belonging to different linkage groups assort independently in accordance with Mendel's second law? it...
Page ii - Institute. (Second printing. ) STELLAR MOTIONS. With Special Reference to Motions Determined by Means of the Spectrograph. By WILLIAM WALLACE CAMPBELL, Sc.D., LL.D., Director of the Lick Observatory, University of California. (Second printing.) PROBLEMS OF GENETICS.
Page ii - England. (Second printing.) THE PROBLEM OF VOLCANISM. By JOSEPH PAXSON IDDINGS, PH.B., Sc.D. (Second printing.) PROBLEMS OF AMERICAN GEOLOGY. By WILLIAM NORTH RICE, FRANK D. ADAMS, ARTHUR P. COLEMAN, CHARLES D. WALCOTT, WALDEMAR LINDGREN, FREDERICK LESLIE RANSOME, and WILLIAM D. MATTHEW. (Second printing.) ORGANISM AND ENVIRONMENT AS ILLUSTRATED BY THE PHYSIOLOGY OF BREATHING. By JS HALDANE, MA, MD, FRS, HON.
Page 25 - Mendel's first law, and in consequence each germ-cell comes to contain one set only; it states that the members belonging to different linkage groups assort independently in accordance with Mendel's second law; it states that an orderly interchange — crossing-over — also takes place, at times, between the elements in corresponding linkage groups; and it states that the frequency of crossing-over furnishes evidence of the linear order of the elements in each linkage group and of the relative position...
Page ii - NERNST, Professor and Director of the Institute of Physical Chemistry in the University of Berlin.
Page ii - SILLIMAN MEMORIAL LECTURES PUBLISHED BY YALE UNIVERSITY PRESS ELECTRICITY AND MATTER. By JOSEPH JOHN THOMSON, D.SC., LL.D., PH.D., FRS, Fellow of Trinity College and Cavendish Professor of Experimental Physics, Cambridge University. (Fourth printing.) THE INTEGRATIVE ACTION OF THE NERVOUS SYSTEM.
Page v - Mrs. Hepsa Ely Silliman Memorial Lectures. It , , was the belief of the testator that any orderly presentation of the facts of nature or history contributed to the end of this foundation more effectively than any »,' attempt to emphasize the elements of doctrine or of creed; and he therefore provided that lectures on dogmatic or polemical theology should be excluded from the scope of this foundation, and that the subjects should be selected rather from the domains of natural science o , ., and history,...
Page v - IN the year 1883 a legacy of eighty thousand dollars was left to the President and Fellows of Yale College in the city of New Haven, to be held in trust, as a gift from her children, in memory of their beloved and honored mother Mrs. Hepsa Ely Silliman. On this foundation Yale College was requested and directed to establish an annual course of lectures designed to illustrate the presence and providence, the wisdom and goodness of God, as manifested in the natural and moral world. These were to be...
Page 10 - They spoke of these results as due to repulsion between the combinations purple and long and red and round, that went from opposite parents. Today these relations are called linkage. By linkage we mean that when certain characters enter a cross together, they tend to remain together in later generations, or, stated in a negative way, certain pairs of characters do not assort at random. It would seem, then, so far as linkage holds, that there are limits to the subdivision of the germinal material....
Page 282 - Mendel's theory of heredity postulates that the gene is stable. It assumes that the gene that each parent contributes to the hybrid remains intact in its new environment in the hybrid. ... If a black guinea pig is bred to a white one, the offspring are black. If these are inbred, the offspring are three blacks to one white. The extracted whites breed as true as the original race of whites. The white gene has not been contaminated by the black gene in their sojourn together in the hybrid.