(Sept. 24, 2012) -- In collaboration with scholars at the University of Hawaii and the University of Pennsylvania School of Medicine, a group of researchers led by John McCarrey, the UTSA College of Sciences' Kleberg Distinguished Chair in Cellular and Molecular Biology, and his graduate student Eric de Waal, who recently received his Ph.D. degree from UTSA, have demonstrated that the hormones known as gonadotropins lead to an increase in epimutations in mice produced in vitro.
The findings are important because they call into question the safety of the methods that are commonly used when couples use the in vitro fertilization process to have children.
The epigenome is the mechanism that programs the genome to control gene expression in each type of cell, and this ultimately decides one's outward appearance and influences development. Epimutations can lead to changes in appearance, development or cellular function when they disrupt the normal function of one or more genes in a cell.
Assisted reproductive technologies (ART) such as in vitro fertilization are a commonly accepted practice and account for more than four million children born worldwide so far, however caution persists among some scholars who point out that the long-term safety of these methods remains generally unknown. Most of the people conceived with the help of ART are currently still under the age of 35.
To better understand how ART and epimutations are linked, the scholars compared the frequency of epimutations in mice produced through an ART process called intracytoplasmic sperm injection (ICSI). They found the epimutation rate to be elevated in mice produced by this method when compared to that in naturally conceived mice.
Next, they compared the frequency of epimutations in three groups of mice: (1) mice produced by natural conception, (2) ICSI-derived mice and (3) mice derived through a process called somatic cell nuclear transfer (SCNT), also known as "cloning". They expected the epimutation rates in the cloned SCNT-derived mice to be higher than those in the ICSI mice. They were surprised, however, to find that the ICSI-derived mice had a higher rate of epimutations than the SCNT-derived mice.
The scholars then reasoned that since gonadotropin-stimulated eggs were used to produce both the ICSI and SCNT-derived offspring, but the nucleus in the egg used for SCNT was then replaced with another nucleus that had not been stimulated with gonadotropin, the lingering effects of gonadotropin exposure in the ICSI-derived offspring must be related to the higher incidence of epimutations in these mice. To test this idea, they subjected female mice to gonadotropin stimulation and then allowed the mice to reproduce naturally to isolate the effects of gonadotropins.
Ultimately, they found that the offspring produced from females subjected to gonadotropin stimulation displayed the same elevated incidence of epimutations they observed in the mice produced by ICSI, confirming that gonadotropin stimulation is a significant factor in inducing epimuations.
Although the mouse sample size the researchers used was small, McCarrey says the findings warrant some caution about the methods associated with ART and call for additional study to determine if the findings hold true in humans.
"ART now accounts for one to four percent of all births in developed countries, so we must work to make this process as completely safe as possible" said McCarrey. "Our results suggest that gonadotropin stimulation, which is typically used in every ART procedure, contributes to the formation of epimutations in the offspring produced. We want to understand why this happens, how it happens and what long-term effects this causes."
The research is available in Human Molecular Genetics.
The CACP 2016-2017 Speaker Series continues with architect and writer Jason Griffiths of the University of Arizona and Jason Griffiths Architecture. His practice is based on a multidisciplinary approach.
Buena Vista Building, Aula Canaria Auditorium (BVB 1.328), Downtown Campus
UTSA's Department of Music hosts Dr. David Huron from Ohio State University as part of the Donald Hodges lecture series. Huron is a Canadian arts and humanities distinguished professor at Ohio State University.
John Peace Library, UTSA Faculty Center, (JPL 4.04.22), Main Campus
The UTSA community is encouraged to donate blood and save a life. Donors will also receive a free t-shirt.
H-E-B University Center parking lot, Main Campus
Dr. Stephanie Westney (violin) presents a concert of Mozart compositions as performed by herself and other talented musicians from the university and surrounding area. This concert is free and open to the public.
Arts Building, Recital Hall (ARTS 2.03.02), Main Campus
The Student Center for Community Engagement and Inclusion annually hosts a Volunteer Opportunities Fair to allow students, faculty and staff to learn about volunteer and service-learning opportunities in the San Antonio area.
University Center, 1st floor corridor, Main Campus
Join the conversation about the experiences of military-connected families in transition. Free parking in the Cattleman Square (along Buena Vista Street). The event is free and open to the public.
Frio Street Building, Riklin Auditorium (FS 1.406), Downtown Campus
School district superintendents and other district leaders responsible for bilingual and ESL programs' administration and accountability learn about cultural literacy, language, and diversity in the community.
Recruiters from across the STEM fields will be present with full-time, part-time and/or internship opportunities. Dress professional and bring plenty of resumes.
Convocation Center, Main Campus
Recruiters from across all fields looking to hire students with all different majors will be present at this event looking to hire for their full-time and/or internship opportunities. Professional dress is required. Bring plenty of resumes.
Convocation Center, Main Campus
The Civic Engagement Summit is an opportunity to celebrate and showcase UTSA's commitment to civic engagement through a myriad of efforts by students, faculty and staff, highlighting the significant ways the university impacts the local community.
H-E-B University Center Ballroom, (HUC 1.104), Main Campus
The Department of Demography presents Dr. Rodolfo Cruz Peñeiro of El Colegio de la Frontera Norte. His presentation is titled "Changes in the Migratory Dynamics of the Northern Mexican Border." This event is free and open to the public.
Monterrey Bldg., (MNT 3.240), UTSA Downtown Campus
Grab your friends, family, kids and dog for this annual fun run on the UTSA Main Campus benefititng the UTSA Alumni Association.
Convocation Center, Main Campus
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