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THE ORIGIN OF CLOSED CIRCLES OF FIVE CHROMOSOMES IN OENOTHERA
Author(s) -
Cleland Ralph E.
Publication year - 1967
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1967.tb10725.x
Subject(s) - biology , genetics , chromosome , oenothera , evolutionary biology , gene
Circles in Oenothera are normally composed of even numbers of chromosomes. Two cases of trisomic hybrids with closed circles containing an odd number of chromosomes are here reported. The first of these appeared to contain β Trois Pistoles I and h Mateo and had a closed circle of 5, an open chain of 8, and a pair; or chains of 9 and 4 plus a pair. The second hybrid seemed to contain α Trois Pistoles II and β Palmer Lake and had a closed circle of 5 and an open chain of 10. It was possible to analyze in considerable detail the situation in the first of these. The chromosome 5·12 or 11·6 of or Trois Pistoles I was present in this trisomic, which arose either through the simple addition of 5·12 or 11·6 to the β Trois Pistoles I complement contributed through the egg, or through double non‐disjunction. If it were a trisomic of the former type it contained only one chromosome of α Trois Pistoles I. If it arose through double non‐disjunction, the minimum it could have had would be the equivalent of two α Trois Pistoles I chromosomes, and it might theoretically have had up to the equivalent of 5 chromosomes. It showed, however, no influence of α Trois Pistoles I in its phenotype, although the two Trois Pistoles I complexes produce very different phenotypes. It is probable, therefore, that the trisomic arose as a result of simple addition of 5·14 or 11·6 of α Trois Pistoles I to the β Trois Pistoles I complex received from the mother.