Abstract In larval salivary gland chromosomes of Chironomus plmosus, isolated by an osmic vapor technique, the following results were obtained by micro-manipulation: The chromosomes will withstand about 100 per cent elongation without permanent deformation, and about 300 per cent before breaking. Most of the elongation occurs in the inter-band regions. Breakage occurs straight across the chromosome at right angles to the long axis. There are indications of a volume increase during stretch. Under stress, diagonal and crisscross striations appear in the inter-band regions. In some instances these can be seen to be formed by the apposition of the walls of vesicles from an originally honeycomb-like structure. The striations are regarded as artifacts rather than genonemata. No evidence of any regular longitudinal differentiation was obtained in attempts to “shred” the chromosomes and to separate the synapsed homologs. After ether treatment, chromosomes are plastic, suggesting a possible role of lipoid in bonding the fabric. The elasticity, and certain other properties of salivary gland chromosomes suggest a tentative chemical comparison with those of fibrous proteins. A review of micromanipulation work on chromosomes is included. This content is only available as a PDF. Author notes *This work was done at the Department of Embryology, Carnegie Institution of Washington, Baltimore, Maryland, and at the Marine Biological Laboratory, Woods Hole, Mass., as part of a series of chromosome studies made in the laboratory of Dr. C. W. Metz with the support of the Rockefeller Foundation. The writer is much indebted to Dr. Metz for advice and encouragement The Carnegie Institution generously bore the c st of the plates, which were prepared with the aid of Mr. Chester Reather of that institution and Mr. Ray Maas and Mrs. H. D. Stalker of the University of Rochester. The assistance of Rochester colleagues and of Professors Chambers and Mast with the manuscript is acknowledged with pleasure. © Oxford University Press

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Block That Stenosis!

1942 Journal of Heredity

doi: 10.1093/oxfordjournals.jhered.a105079pmid: N/A

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GENETIC DIFFERENCES IN THE SOCIAL BEHAVIOR OF INBRED STRAINS OF MICE

SCOTT, J. P.

1942 Journal of Heredity

doi: 10.1093/oxfordjournals.jhered.a105080pmid: N/A

Abstract The fighting behavior of males of several inbred stocks of house mice belonging to the Jackson Laboratory was studied, and indications of genetic differences were found between all except certain closely related strains. The C57 blacks (subline 10) and C3H agouti strains showed wide differences, little variability, and no overlap under the conditions tested. These, together with the C (Bagg) albinos are concluded to be well adapted for use in bio-sociological research. The basic characteristics of the three strains appear to be: a. C57—high degree of activity, tendency to make close contact with physical environment and other mice, and, under certain conditions, pacific behavior. b. C3H—moderate degree of activity, tendency to avoid close contacts, easily evoked hair-fluffing reaction. c. C—moderate activity and aggressiveness, no extreme behavior traits. These mice are widely different from human beings in social activity but have certain special research uses because of their small size and predictable behavior. This content is only available as a PDF. © Oxford University Press

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“OFF THE RECORD” TWINS AND MICETwo More Publication “Ghosts”

R. C., R. C.

1942 Journal of Heredity

doi: 10.1093/oxfordjournals.jhered.a105081pmid: N/A

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A NEW PEDIGREE OF RECURRENT BULLOUS ERUPTION OF THE FEET

HALDANE, J. B. S.; POOLE, ROSAMUNDE

1942 Journal of Heredity

doi: 10.1093/oxfordjournals.jhered.a105082pmid: N/A

Abstract A pedigree of recurrent blistering of the feet, due to an autosomal dominant gene, is described. The condition probably originated by mutation. The same or a very similar condition has previously been described in two other families by Cockayne. This content is only available as a PDF. © Oxford University Press

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TWINS AND THE STUDY OF DELINQUENCY

SCHWESINGER, GLADYS C.

1942 Journal of Heredity

doi: 10.1093/oxfordjournals.jhered.a105083pmid: N/A

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THE INHERITANCE OF “WHITE-BELLY” IN THE HOUSE MOUSE

KALISS, NATHAN

1942 Journal of Heredity

doi: 10.1093/oxfordjournals.jhered.a105084pmid: N/A

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ARE INSECTS PEOPLE?

SPILLMAN, RAMSAY

1942 Journal of Heredity

doi: 10.1093/oxfordjournals.jhered.a105085pmid: N/A

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A NATURAL AMPHIDIPLOID FROM AN ONION SPECIES HYBRID

JONES, HENRY A.; CLARKE, ALFRED E.

1942 Journal of Heredity

doi: 10.1093/oxfordjournals.jhered.a105086pmid: N/A

Abstract A fertile amphidiploid has been obtained from a cross between Allium cepa var. Australian Brown and A. fistulosum type Nebuka. Second generation plants are very uniform in appearance and set seed readily. This amphidiploid shows greater vegetative vigor than either parent, as evidenced by increased height, larger sto-mata, larger flowers, larger pollen grains, greater weight of seed, and more rapid growth of seedlings. It is a perennial like Nebuka. The haploid number of chromosomes in the amphidiploid is sixteen. Meiotic behavior is fairly regular. Sixteen bi-valents are generally found at first meta-phase. Fragments, chromatin bridges, and micronuclei were observed but were not as common as in the diploid hybrid. During meiosis both the random and localized type of chiasma formation are found in different bivalents in the same cell. This content is only available as a PDF. © Oxford University Press

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