Homologous recombination occurs frequently at innate GT microsatellites in normal somatic and germ cells in vivo

Jianbo Zheng,Chen Luo,Heng Li,Xiangfang Liu,Lei Sun,Qi Zhang

doi:10.1186/s12864-018-4758-y

Abstract

BackgroundIn somatic cells, homologous recombination (HR) is a rare event caused by eventual DNA double-strand breaks (DSBs). In contrast, germ cells show high frequency of HR caused by programmed DSBs. Microsatellites are prone to DSBs during genome replication and, thereby, capable of promoting HR. It remains unclear whether HR occurs frequently at microsatellites both in normal somatic cells and germ cells in a similar manner.ResultsBy examining the linkage pattern of multiple paternal and maternal markers flanking innate GT microsatellites, we measured HR at the GT microsatellites in various somatic cells and germ cells in a goldfish intraspecific heterozygote. During embryogenesis, the HR products accumulate gradually with the increase of the number of cell divisions. The frequency of HR at the GT microsatellites in advanced embryos, adult tissues and germ cells is surprisingly high. The type of exchanges between the homologous chromosomes is similar in normal advanced embryos and germ cells. Furthermore, a long GT microsatellite is more active than a short one in promoting HR in both somatic and germ cells.ConclusionsHR occurs frequently at innate GT microsatellites in normal somatic cells and germ cells in a similar manner.

Highlights

In somatic cells, homologous recombination (HR) is a rare event caused by eventual DNA double-strand breaks (DSBs)
HR in somatic cells is thought to be a rare event caused by eventual DNA double-strand breaks (DSBs), which frequently leads to non-crossover recombination and has potential detrimental effects due to loss of heterozygosity (LOH) [1,2,3]
(GT)n motif 1 is much longer in Chinese goldfish (CGF) strain than in Japanese goldfish (JGF) strain (Fig. 1b, c)

Summary

Introduction

Homologous recombination (HR) is a rare event caused by eventual DNA double-strand breaks (DSBs). Germ cells show high frequency of HR caused by programmed DSBs. Microsatellites are prone to DSBs during genome replication and, thereby, capable of promoting HR. Microsatellites are prone to DSBs during genome replication and, thereby, capable of promoting HR It remains unclear whether HR occurs frequently at microsatellites both in normal somatic cells and germ cells in a similar manner. HR in somatic cells is thought to be a rare event caused by eventual DNA double-strand breaks (DSBs), which frequently leads to non-crossover recombination and has potential detrimental effects due to loss of heterozygosity (LOH) [1,2,3].

Methods

Results

Discussion

Conclusion