Claim · model-written summary
Rings of 12 to 18 chromosomes from interpopulation crosses had more irregular segregation and high sterility.
- Taxon
- Clarkia dudleyana
Clarkia dudleyanat0 - Material
- larger rings of 12 to 18 chromosomese0
- Outcome
- segregation is much more irregular and leads to high sterilitye0
Not reportedGeneCompoundOrgan / stageInteractorInteractor roleSecond interactorSecond interactor roleTreatmentComparatorSettingDirectionValueQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the larger rings of 12 to 18 chromosomes, derived from interpopulation crosses, segregation is much more irregular and leads to high sterility”
t0“Clarkia dudleyana”
Title
Chromosomal Differentiation in Clarkia dudleyana
Richard Snow American Journal of Botany 1960. doi:10.2307/2439611
Other claims from this paper (14)
- Observation Seventeen point one percent of sampled individuals were heterozygous for reciprocal translocations.
- Observation About 2% of examined plants had supernumerary chromosomes.
- Observation Translocation heterozygotes were concentrated near the geographical center of the species range.
- Observation Most populations had none or few translocation heterozygotes.
- Observation One colony had 69% heterozygotes among 42 sampled plants.
- Observation At least five chromosome arrangements were observed at that locality.
- Observation Hybrids between colonies were invariably translocation heterozygotes.
- Observation The largest hybrid chromosome association was a chain of all 18 chromosomes.
- Association Geographical separation was not correlated with cytological differentiation.
- Observation Heterozygotes with rings of 4 or 6 chromosomes were highly fertile.
- Mechanism Regular alternate disjunction of ring chromosomes explains high fertility of small-ring heterozygotes.
- Observation The authors suggest that heterozygotes may have selective advantage in some localities.
- Mechanism The authors postulate habitat-specific selection for chromosome arrangement homozygosity.
- Mechanism The authors suggest Oenothera complex heterozygotes arose through hybridization of differentiated races.