Effect of Maternal Age on Chromosome Aberrations and Telomere Quantity in Chick Embryos

Abstract

The rate of fetus with abnormal chromosomes increase with maternal age. Nondisjunction of aging oocyte chromosome is a major reason for the increased rate of abnormalities. Telomeres are the ends of eukaryotic chromosome, which are essential for chromosome stability and are related in cell senescence. This study was carried out to analyze the chromosome aberration rate and amount of telomeric DNA in chick embryo along with maternal age. Fertilized eggs and blood were sampled from White Leghorn layers starting at 20 weeks through to 70 weeks age at 10 weeks interval. Chromosome aberration rate was analyzed by karyotyping. The amounts of telomeric DNA in embryonic cells and lymphocytes were quantified by Quantitative Fluorescence in situ Hybridization method. The chromosome aberration rate in chick embryos significantly differed with maternal age. The chromosome aberration rate increased at early laying period and beyond 70 weeks of maternal age. Therefore, chromosome aberration rate was affected by maternal age due to ovulated oocytes state. However, the amount of telomeric DNA on embryonic cells did not differ significantly with maternal age. Thus, maternal age does not affects telomere quantity in their embryos due to cellular reprograming at early embryonic stage after fertilization.

Inheritance and Heritability of Telomere Length in Chicken

“…또한 남성의 germline cell들의 텔로미어 길이는 높은 telomerase 발현에도 불 구하고 매우 다양한 변이를 나타내고 있는데, 자식들의 텔로 미어 길이는 paternal gamate의 텔로미어 길이와 밀접한 관 련이 있음을 제시하여 텔로미어 길이가 모보다는 부의 영향 을 받는다고 하였다 (Nordfjall et al, 2005(Nordfjall et al, , 2010Kimura et al, 2008 (Wilmut et al, 1997;Shiels et al, 1999), 이후 유사 연구들에서 어떠한 연령의 공여 개체의 세 포이던 간에 텔로미어 길이는 배반포 단계에서 repro-gramming이 일어나 발생 시 일정 길이로 신장된다는 결과와는 일치되는 양상이다 (Lanza 등, 2000). 특히, 닭의 경우 모계 연령에 따른 생산 배아의 텔로미어 함량 비교 분석에서 모 체의 산란 연령과 배아의 텔로미어 함량 간에는 거의 상관 관계가 없는 것으로 보고하고 있다 (Lee et al, 2009 …”