English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The sex ch romat in body is an oval or round ch roma t in mass approximate ly 1 micron in d iameter lying against the inner por t ion of the nuclear membrane . In h u m a n tissue it is present in abou t 20 to 40 per cent of female cells and is absent in male cells. T he sex ch romat in of somatic in terphase nuclei is though t to be derived from a por t ion of a single heteropyknot ic X chromosome (1, 2). L ima-de-Far ia (4) has demonst ra ted asynchrony in D N A synthesis of the chromosomes of Melanoplus differentialis and Secale cereale with the dupl ica t ion of he te rochromat in occurr ing later than euchromat in . T he two X chromosomes of the normal female Chinese hamster differ morphologically and in their pa t t e rn of D N A synthesis in vitro (6-8). Taylor (6) found tha t the short a rm of one X chromosome was dupl ica ted dur ing the first half of the period of D N A synthesis, whereas the long a r m and the ent ire other X chromosome repl icated dur ing the last port ion of the D N A synthesis period. Mor i sh ima et el. (5) showed tha t in h u m a n leukocytes grown in culture a late replicat ing X chromosome was found in normal female subjects. The late repl icat ing X chromosome was not found in cells cul tured from three normal males. These authors presented evidence tha t it is the late repl icat ing X chromosome tha t produces the sex ch romat in body of in terphase nuclei. The present study was under t aken to demonstrate asynchrony of D N A synthesis wi th in normal h u m a n interphase nuclei with par t icular reference to the sex chromat in .

ASYNCHRONOUS DNA SYNTHESIS OF SEX CHROMATIN IN HUMAN INTERPHASE NUCLEI