Trisomic and monosomic (aneuploid) embryos account for at least 10% of human
pregnancies and, for women nearing the end of their reproductive lifespan, the incidence�…

In mammals, fertilization typically involves the ovulation of one or a few eggs at one end of
the female reproductive tract and the entry of millions of sperm at the other. Given this�…

PIP: Trisomy, occurring in at least 4% of pregnancies, is the most common chromosome
abnormality in humans. The majority of trisomies are associated with single additional�…

Background: There is increasing concern that exposure to man-made substances that mimic
endogenous hormones may adversely affect mammalian reproduction. Although a variety of�…

Analysis of recombination between loci (linkage analysis) has been a cornerstone of human
genetic research, enabling investigators to localize and, ultimately, identify genetic loci�…

Mitotic chromosome segregation is facilitated by the cohesin complex, which maintains
physical connections between sister chromatids until anaphase. Meiotic cell division is�…

Critical events of oogenesis occur during three distinct developmental stages: meiotic
initiation in the fetal ovary, follicle formation in the perinatal period, and oocyte growth and�…

During a cytogenetic study of spontaneous abortions, successive abortions from 40 couples
were karyotyped. The chromosome constitutions of the first and second abortions were�…

In eukaryotes, diploid cells give rise to haploid cells via meiosis, a program of two cell
divisions preceded by one round of DNA replication. Although key molecular components of�…

Mental retardation and hypotonia are found in virtually all Down syndrome (DS) individuals,
whereas congenital heart defects (CHDs) are only present in a subset of cases. Although�…