News | Study Identifies Gene-Replication Errors as a Major Cause of IVF Embryo Failure
In vitro fertilization (IVF) has brought hope to many people who cannot conceive naturally. Yet IVF embryo failure remains common, with many fertilized eggs stopping development within days, often because of chromosomal abnormalities. A study from Columbia University Vagelos College of Physicians and Surgeons found that spontaneous errors during DNA replication may be a major cause of IVF embryo failure. The finding offers a new direction for reproductive medicine and research aimed at improving IVF success rates.
Study Finds Replication Errors Occur Early
IVF embryos begin dividing about 24 hours after fertilization. During cell division, all 46 chromosomes, containing more than three billion DNA base pairs, must be copied accurately so that each daughter cell receives a complete genome. Replication errors frequently occur during these early divisions, leaving some embryonic cells with an abnormal number of chromosomes.
Dr. Dieter Egli, study lead and assistant professor of developmental cell biology at Columbia University, said: "Cell division in early embryos is an exceptionally demanding process. Copying the genome is complex, and even a small error may cause chromosomal abnormalities. These problems occur during the early stages of DNA replication, not during later cell division as earlier research suggested."
Errors Arise from Spontaneous Barriers to DNA Replication
The researchers found that DNA replication errors are associated with obstacles within the DNA double helix. These obstacles pause or stall replication, causing DNA breaks and abnormal chromosome numbers. Dr. Egli noted: "DNA replication errors are the root cause of chromosome-segregation failure. This issue was long overlooked because scientists could not explain why embryos would allow genome integrity to be compromised at such a critical stage."
Underlying Cause of Arrested IVF Embryo Development
The study also found that replication errors can appear during the first cell division after fertilization and may continue as division proceeds. If too many cells in the early embryo have chromosomal abnormalities, the embryo cannot continue developing.
Dr. Jenna Turocy, a fertility specialist at Columbia University Fertility Center and study co-author, said: "Many women undergoing fertility treatment need several IVF cycles to become pregnant, and some never succeed. This is extremely expensive and places a tremendous emotional burden on patients."
Outlook: New Hope for Improving IVF Success
The study offers a new direction for IVF research. By better understanding errors in DNA replication, researchers hope to develop ways to reduce genetic abnormalities and the risk of embryo failure. The team plans to study DNA damage during replication further to better understand how normal and disease-related variants affect human reproduction. Over time, this work may improve IVF success rates.
The study was conducted by Columbia University Vagelos College of Physicians and Surgeons and collaborating institutions and was published online in Cell on July 19, 2022.
News | Study Identifies Gene-Replication Errors as a Major Cause of IVF Embryo Failure
News | Study Identifies Gene-Replication Errors as a Major Cause of IVF Embryo Failure
In vitro fertilization (IVF) has brought hope to many people who cannot conceive naturally. Yet IVF embryo failure remains common, with many fertilized eggs stopping development within days, often because of chromosomal abnormalities. A study from Columbia University Vagelos College of Physicians and Surgeons found that spontaneous errors during DNA replication may be a major cause of IVF embryo failure. The finding offers a new direction for reproductive medicine and research aimed at improving IVF success rates.
Study Finds Replication Errors Occur Early
IVF embryos begin dividing about 24 hours after fertilization. During cell division, all 46 chromosomes, containing more than three billion DNA base pairs, must be copied accurately so that each daughter cell receives a complete genome. Replication errors frequently occur during these early divisions, leaving some embryonic cells with an abnormal number of chromosomes.
Dr. Dieter Egli, study lead and assistant professor of developmental cell biology at Columbia University, said: "Cell division in early embryos is an exceptionally demanding process. Copying the genome is complex, and even a small error may cause chromosomal abnormalities. These problems occur during the early stages of DNA replication, not during later cell division as earlier research suggested."
Errors Arise from Spontaneous Barriers to DNA Replication
The researchers found that DNA replication errors are associated with obstacles within the DNA double helix. These obstacles pause or stall replication, causing DNA breaks and abnormal chromosome numbers. Dr. Egli noted: "DNA replication errors are the root cause of chromosome-segregation failure. This issue was long overlooked because scientists could not explain why embryos would allow genome integrity to be compromised at such a critical stage."
Underlying Cause of Arrested IVF Embryo Development
The study also found that replication errors can appear during the first cell division after fertilization and may continue as division proceeds. If too many cells in the early embryo have chromosomal abnormalities, the embryo cannot continue developing.
Dr. Jenna Turocy, a fertility specialist at Columbia University Fertility Center and study co-author, said: "Many women undergoing fertility treatment need several IVF cycles to become pregnant, and some never succeed. This is extremely expensive and places a tremendous emotional burden on patients."
Outlook: New Hope for Improving IVF Success
The study offers a new direction for IVF research. By better understanding errors in DNA replication, researchers hope to develop ways to reduce genetic abnormalities and the risk of embryo failure. The team plans to study DNA damage during replication further to better understand how normal and disease-related variants affect human reproduction. Over time, this work may improve IVF success rates.
The study was conducted by Columbia University Vagelos College of Physicians and Surgeons and collaborating institutions and was published online in Cell on July 19, 2022.
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