On the purely motherly character of the hybrids produced from the eggs of Strongylocentrotus

Hagedoorn, A.

doi:10.1007/bf02161785

Cited by 16 publications

(14 citation statements)

References 15 publications

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“…Compared with a number of other sea urchin crosses so far reported (8,9,16,18,22,24,25,27,28,30,36,39,40), the hybrid of D. excentricus and S. purpuratus was thought to provide an ideal material for studies on how embryonic temperature sensitivity is determined. In the present work I examined the temperature sensitivity of hybrids and compared it with those of embryos from conspecific parents of both species.…”

Section: Introductionmentioning

confidence: 99%

“…Embryonic temperature sensitivity differs markedly between Dendraster excentricus and Strongylocentrotus purpuratus, and Whiteley and Baltzer (40) devised a method of preparing hybrids between these species at a very high rate (above 80%). Compared with a number of other sea urchin crosses so far reported (8,9,16,18,22,24,25,27,28,30,36,39,40), the hybrid of D. excentricus and S. purpuratus was thought to provide an ideal material for studies on how embryonic temperature sensitivity is determined. In the present work I examined the temperature sensitivity of hybrids and compared it with those of embryos from conspecific parents of both species.…”

Section: Introductionmentioning

confidence: 99%

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Temperature Sensitivity of a Hybrid between Two Species of Sea Urchin Differing in Thermotolerance

Fujisawa

1993

Dev Growth Differ

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Eggs of Dendraster excentricus can be fertilized with sperm of Strongylocentrotus purpuratus at a high success rate according to Whiteley and Baltzer's method. The resulting hybrids are well suited for investigations of the factors determining embryonic thermosensitivity, because the embryos of both the above species differ significantly with regard to egg size, blastula shape, and particularly thermotolerance and the temperature dependence of their developmental rate. Morphologically, the hybrids show some paternally inherited traits, but their thermosensitivity is strictly determined by the egg cytoplasm.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Temperature Sensitivity of a Hybrid between Two Species of Sea Urchin Differing in Thermotolerance

Fujisawa

1993

Dev Growth Differ

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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%

“…Thus we have a large amount of evidence with regard to the inheritance of the skeleton, and this is chiefly remarkable for its very conflicting nature ; frequently investigators working on the same material in the same laboratory have obtained diametrically opposite results-as for instance Boveri (9) and Morgan (65) at Naples, and Loeb (54) and H agedoorn (38) working at Pacific Grove, California.…”

Section: Eacutusmentioning

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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“…In 1909 Hagedoorn (9), working in Loeb's Laboratory, Pacific Grove, O~l., crossed Strongylocentrotus pU1puratns and S. franciscanus and found a purely motherly dominance in the shapes of the skeletal apical rods. In the following year Loeb, King, and Moore (10) repeated these experiments at the same place, but reached very different results.…”

Section: Introduction and Previous Workmentioning

confidence: 99%