Recombination and non-disjunction: Molecular studies of trisomy 16

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · American Journal of Human Genetics

OSTI ID:133301

Hassold, T; Merrill, M; Adkins, K ^[1]

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1. Case Western Reserve Univ., Cleveland, OH (United States); and others

Trisomy 16 is the most common trisomy in humans, occurring in at least 1% of all clinically recognized pregnancies. It is thought to be completely maternally age dependent, thus it provides a useful model for studying the association of increasing maternal age and non-disjunction. We recently initiated a molecular study of non-disjunction of chromosome 16 to determine the parent and meiotic stage of origin of the extra chromosome, and to study the possible association of non-disjunction and aberrant recombination. To date, we have analyzed 62 spontaneous abortions with trisomy 16. All trisomies were maternally-derived and in virtually all the error occurred at meiosis I. Thus, our results are consistent with the idea that a single, maternal age-related non-disjunctional mechanism is responsible for the vast majority of cases of trisomy 16. In studies of genetic recombination, we have used a panel of 25 chromosome 16 markers to examine the frequency and location of crossing-over in the non-disjunctional meioses. Our results indicate a highly significant reduction in recombination, with 20% of cases having no detectable exchanges, 50% a single exchange and 30% two exchanges; no multiple exchange events were identified. This suggests that reduced - but not absent - recombination is the important predisposing factor, since most cases had at least one exchange. Additionally, our data indicate an altered distribution of crossing-over in trisomy 16, as we rarely observed exchanges in the proximal long and short arms. Thus, it may be that, at least for chromosome 16, the association between maternal age and trisomy is due to diminished recombination, particularly in the proximal regions of the chromosome.

• OSTI ID: 133301
• Report Number(s): CONF-941009--
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
AGE DEPENDENCE
ANIMAL CELLS
BIOLOGICAL MARKERS
CHROMOSOMAL ABERRATIONS
CROSSING-OVER
FEMALES
GENE RECOMBINATION
GENES
HEREDITARY DISEASES
HUMAN CHROMOSOME 16
MEIOSIS
MENTAL DISORDERS
NON-DISJUNCTION
PATIENTS