Linked Life Data

9285774

Source:http://linkedlifedata.com/resource/pubmed/id/9285774

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1998-2-2
pubmed:abstractText
Recent studies of trisomy 21 have shown that altered levels of recombination are associated with maternal non-disjunction occurring at both meiosis I (MI) and meiosis II (MII). To comprehend better the association of recombination with nondisjunction, an understanding of the pattern of meiotic exchange, i.e. the exchange of genetic material at the four-strand stage during prophase, is required. We examined this underlying exchange pattern to determine if specific meiotic configurations are associated with a higher risk of non-disjunction than others. We examined the crossover frequencies of chromosome 21 for three populations: (i) normal female meiotic events; (ii) meiotic events leading to MI non-disjunction; and (iii) those leading to MII non-disjunction. From these crossover frequencies, we estimated the array of meiotic tetrads that produced the observed crossovers. Using this approach, we found that nearly one-half of MI errors were estimated to be achiasmate. The majority of the remaining MI bivalents had exchanges that clustered at the telomere. In contrast, exchanges occurring among MII cases clustered at the pericentromeric region of the chromosome. Unlike the single exchange distributions, double exchanges from the non-disjoined populations seemed to approximate the distribution in the normal population. These data suggest that the location of certain exchanges makes a tetrad susceptible to non-disjunction. Specifically, this susceptibility is associated with the distance between the centromere and closest exchange. This result challenges the widely held concept that events occurring at MII are largely independent of events occurring at MI, and suggests that all non-disjunction events may be initiated during MI and simply resolved at either of the two meiotic stages.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0964-6906
pubmed:author
pubmed:issnType
Print
pubmed:volume
6
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1391-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Characterization of susceptible chiasma configurations that increase the risk for maternal nondisjunction of chromosome 21.
pubmed:affiliation
Department of Genetics, Emory University School of Medicine, Atlanta, GA, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't