Christian S. Ottolini

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Crossover recombination reshuffles genes and prevents errors in segregation that lead to extra or missing chromosomes (aneuploidy) in human eggs, a major cause of pregnancy failure and congenital disorders. Here we generate genome-wide maps of crossovers and chromosome segregation patterns by recovering all three products of single female meioses.(More)
INTRODUCTION Aneuploidy (the presence of extra or missing chromosomes) arises primarily through chromosome segregation errors in the oocyte at meiosis I but the details of mechanism by which such errors occur in humans are the subject of some debate. It is generally believed that aneuploidy arises primarily as a result of segregation of a whole chromosome(More)
Preimplantation genetic diagnosis (PGD) for monogenic disorders has the drawback of time and cost associated with tailoring a specific test for each couple, disorder, or both. The inability of any single assay to detect the monogenic disorder in question and simultaneously the chromosomal complement of the embryo also limits its application as separate(More)
Preimplantation genetic diagnosis (PGD) of single gene defects by genetic analysis of single or small numbers of cells biopsied from in vitro fertilization (IVF) embryos is clinically well-established. Targeted haplotyping by multiplex fluorescent polymerase chain reaction (PCR) of closely linked or intragenic short tandem repeat (STR) markers combined with(More)
Preimplantation genetic screening (PGS) for embryo aneuploidy using embryo biopsy is a widely available technique used to select embryos for transfer following IVF for certain patient populations. Since its introduction, there has been an ongoing search for a non-invasive technique to perform PGS. Such an advance would revolutionize the field of IVF(More)
OBJECTIVE To study the effect of artificial oocyte activation (AOA) on chromosome segregation errors in the meiotic divisions. DESIGN Prospective cohort study with historical control. SETTING Private/academic IVF centers. PATIENT(S) Fifty-six metaphase II oocytes were donated from 12 patients who had undergone IVF between June 2008 and May 2009. (More)
Blastocyst biopsy is now widely used for both preimplantation genetic screening (PGS) and preimplantation genetic diagnosis (PGD). Although this approach yields good results, variable embryo quality and rates of development remain a challenge. Here, a case is reported in which a blastocyst was biopsied for PGS by array comparative genomic hybridization on(More)
We have developed a protocol for the generation of genome-wide maps (meiomaps) of recombination and chromosome segregation for the three products of human female meiosis: the first and second polar bodies (PB1 and PB2) and the corresponding oocyte. PB1 is biopsied and the oocyte is artificially activated by exposure to calcium ionophore, after which PB2 is(More)
Following in vitro fertilisation (IVF), only about half of normally fertilised human embryos develop beyond cleavage and morula stages to form a blastocyst in vitro. Although many human embryos are aneuploid and genomically imbalanced, often as a result of meiotic errors inherited in the oocyte, these aneuploidies persist at the blastocyst stage and the(More)
27 Aneuploidy is prevalent in human preimplantation embryos and is the leading cause 28 of pregnancy loss. Many aneuploidies arise during oogenesis, increasing in 29 frequency with maternal age. Superimposed on these meiotic aneuploidies are a 30 range of errors occurring during early mitotic divisions of the embryo, contributing to 31 widespread(More)