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Parental chromosome dimensions in Ascaris. A study of the effect of cellular environment on chromosome size
Author(s) -
Hance Robert T.
Publication year - 1927
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1050440106
Subject(s) - biology , cleavage (geology) , ascaris , chromosome , homologous chromosome , embryo , genetics , period (music) , zoology , anatomy , helminths , paleontology , gene , physics , fracture (geology) , acoustics
In the early cleavage stages of Ascaris the homologous chromosomes are of unequal length. Measurements show that these homologues fall into two sharply defined groups suggesting their biparental origin. The shorter are considered to have come from the male. As the age of the embryo increases, these differences between the chromosome mates tend to become less, and it is suggested that at some later period in the history of the animal this difference will entirely disappear in response to the effect of continued existence in a common environment. The length of the chromosomes is very slightly shortened during the early cleavage divisions, while the area of the equatorial cross‐section of the cells becomes enormously reduced.