A comparative study of DNA amount and nuclear dry weight in four different species (Rana catesbeiana, Salmo gairdneri, Gallus domesticus and Homo sapiens).
1. Quantitative electron microscopic and cytophotometric determinations of average nuclear weight, unit weight of chromatin fiber, chromatin fiber diameter and DNA amount were made and compared from lymphocytes in human, chicken, frog and trout. 2. From these determinations the "packing ratio" of DNA in chromatin fibers was calculated. 3. Nuclear mass and DNA amounts were highest in frog and lowest in chicken, while fiber diameter and mass of unit fiber measured highest in trout followed by chicken, frog and man. 4. The packing ratios were 21.4 in chicken, 35.2 in human, 47.0 in trout, 51.1 in frog and show a trend of being lower in amniotes than in anamniotes. 5. As only four species were studied, no conclusions regarding evolutionary implications or relationships between them could be made from these measurements.
Mikel
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UV
Department of Cellular Pathology, Armed Forces Institute of Pathology, Washington, D.C.
Bahr
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GF
D000818:Animals; D002467:Cell Nucleus / Q000737:chemistry* / Q000648:ultrastructure; D002645:Chickens; D002843:Chromatin / Q000737:chemistry; D004247:DNA / Q000097:blood*; D015186:Hominidae; D006801:Humans; D008214:Lymphocytes / Q000648:ultrastructure*; D008854:Microscopy, Electron; D011892:Rana catesbeiana; D012474:Salmon; D013045:Species Specificity
D002843:Chromatin; D004247:DNA