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Chromosome heteromorphism quantified by high-resolution bivariate flow karyotyping
B Trask1, G van den Engh, B Mayall
1Lawrence Livermore National Laboratory, Biomedical Sciences Division, CA 94550.
American Journal of Human Genetics
|November 1, 1989
Summary
Normal chromosomes show significant DNA content variation between parents, especially for chromosomes Y, 21, 22, 15, 16, 13, 14, and 19. This DNA content variation impacts flow karyotype analysis.
Area of Science:
- Genetics
- Cytogenetics
- Molecular Biology
Background:
- Maternal and paternal chromosomes can be distinguished using bivariate flow karyotypes.
- DNA content differences exist among homologous chromosomes within individuals.
Purpose of the Study:
- To quantify DNA content variation among homologous chromosomes in normal individuals.
- To identify chromosome types exhibiting the most significant homologue differences.
Main Methods:
- Bivariate flow karyotyping using Hoechst 33258 and chromomycin A3.
- Analysis of 98 individuals' karyotypes for homologue peak position differences.
- Fluorescence in situ hybridization (FISH) to investigate copy number variations.
Main Results:
- Significant homologue differences observed in an average of four chromosome types per individual.
- Chromosomes Y, 21, 22, 15, 16, 13, 14, and 19 were most heteromorphic.
- Chromosome 21 showed up to a 45% size difference between homologues; copy number variation contributes to this.
Conclusions:
- Normal homologous chromosomes exhibit substantial DNA content variability.
- This variability, particularly in specific chromosomes, must be considered in flow karyotyping.
- Parental flow karyotype data is crucial for detecting de novo rearrangements.