Das Schicksal des mit Radium bestrahlten Spermachromatins im Seeigelei

Hertwig, Günther

doi:10.1007/bf02982877

Cited by 46 publications

(4 citation statements)

References 15 publications

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“…Similar experiments were performed on salamanders (0. Hertwig, 1913), fish (P. Hertwig, 1916; Oppermann, 1913), seaurchins (G. Hertwig, 1912) and on annelids (Packard, 1914(Packard, , 1918. Exposure of frog sperm to ultra-violet radiation, X-rays or trypaflavin (Dalcq, 1931 ;Dalcq & Simon, 1931 ;Rugh, 1939) has been shown to give similar results.…”

Section: Sperm Extracts and Modified Spermmentioning

confidence: 92%

Artificial Parthenogenesis

Tyler

1941

Biological Reviews

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Section: Sperm Extracts and Modified Spermmentioning

confidence: 92%

Artificial Parthenogenesis

Tyler

1941

Biological Reviews

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“…fig. 127)-A number of urchins of this cross (35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45) survived and attained considerable size by the end of the first year. At the time they were about five or six months old their pigmentation was quite different from that shown at present.…”

Section: E Esculentus $ X Eacutus $ ( C F Plate Figs 123-126)-mentioning

confidence: 99%

“…The very slight development of the spines on the aboral surface of this hybrid recalls the condition found in some small Its manifest abnormality renders useless its comparison with the parent forms. (35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45) survived and attained considerable size by the end of the first year. At the time they were about five or six months old their pigmentation was quite different from that shown at present.…”

Section: E Esculentus $ X Eacutus $ ( C F Plate Figs 123-126)-mentioning

confidence: 99%

VIII. On the experimental hybridization of echinoids

1914

Phil. Trans. R. Soc. Lond. B

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The present work was originally undertaken some four years ago, with the object of finding out how readily some of our common sea-urchins could be crossed, and their larvæ reared to a stage when they assumed adult characters. The forms selected for this purpose were Echinus acutus, E. esculentus , and E. miliaris . One of our number (de Morgan) had already reared the larvæ of E. esculentus and E. miliaris , as well as the crosses E. acutus ♀ X E. esculentus ♂ and E. miliaris ♀ X E. esculentus ♂ through metamorphosis. Our early experiments showed that if the right conditions were observed, all the possible crosses between these forms could be reared through metamorphosis. This led to the attempt to discover definite characters in the larval development, more specific and fixed than those hitherto employed as a basis of comparison between normal and hybrid plutei. Moreover, of the three species selected for our experiments, two, E. esculentus and E. acutus , are closely related; while the third, E. miliaris , is but distantly allied to the other two, being usually classed in the separate genus of Psammechinus . Thus, if the hybrids between E. miliaris and E. esculentus , and E. miliaris and E. acutus should prove sterile, on account of the specific differences separating these species, those at least between E. esculentus and E. acutus would, we hoped, yield fertile hybrids, which could be investigated in a second generation. In the numerous papers which have appeared on Echinoderm hybridization, hitherto only the characters of the early pluteus, up to the assumption of the eight-armed condition, have been investigated. In the past it has been held that the early larval characters are sufficiently definite to give a clear answer to all questions of inheritance. The larval skeleton has been adopted as a main basis of comparison between normal and hybrid larvæ; unfortunately, the skeleton, like many of the early larval features, is subject to irregular variation. Under unfavourable circumstances the skeleton frequently tends to develop extra rods and spinous processes, which give it a spurious resemblance to that of other species. Therefore skeletal characters cannot always be safely attributed to hereditary influence. In our experiments we soon came to the conclusion that if any definite advance were to be made in this subject, it would be best to abandon the skeleton, and all the early features of the pluteus, as an index of parental influence, and to find more definite characters in the later larval life, and that we should have rigorously to adhere in our work to two general principles.

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“…Ebenso wie G. Hertwig sucht auch O. Hertwig (1912Hertwig ( bis 1916 die Tatsache, dass das Mittelsttick bei der ersten Furchungsteilung in die eine der beiden ersten Blastomeren tibergeht, als einen Beweis daftir zu verwerten, dass der Kern der alleinige Vererbungstrager sei.…”

Section: ~1unclassified

Die Plastosomentheorie der Vererbung

Meves

1918

Archiv f. mikr. Anat.

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Das Schicksal des mit Radium bestrahlten Spermachromatins im Seeigelei

Cited by 46 publications

References 15 publications

Artificial Parthenogenesis

Artificial Parthenogenesis

VIII. On the experimental hybridization of echinoids

Die Plastosomentheorie der Vererbung

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