Publications by authors named "Yaxin Yao"

4 Publications

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Whole Genome Sequencing Reveals the Effects of Recent Artificial Selection on Litter Size of Bamei Mutton Sheep.

Animals (Basel) 2021 Jan 12;11(1). Epub 2021 Jan 12.

Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China.

Bamei mutton sheep is a Chinese domestic sheep breed developed by crossing German Mutton Merino sheep and indigenous Mongolian sheep for meat production. Here, we focused on detecting candidate genes associated with the increasing of the litter size in this breeds under recent artificial selection to improve the efficiency of mutton production. We selected five high- and five low-fecundity Bamei mutton sheep for whole-genome resequencing to identify candidate genes for sheep prolificacy. We used the FST and XP-EHH statistical approach to detect the selective sweeps between these two groups. Combining the two selective sweep methods, the reproduction-related genes , , , , and were detected. , , and play vital roles in GnRH (gonadotropin-releasing hormone), oxytocin, and estrogen signaling pathway. Moreover, , which had the highest FST value, exhibits demethylase activity. It can affect reproduction by binding the promoters of estrogen-regulated genes, such as (forkhead box A1) and (estrogen receptor 1). Notably, one nonsynonymous mutation (p.S936A) specific to the high-prolificacy group was identified at the TUDOR domain of KDM4B. These observations provide a new opportunity to research the genetic variation influencing fecundity traits within a population evolving under artificial selection. The identified genomic regions that are responsible for litter size can in turn be used for further selection.
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January 2021

Minimally invasive preimplantation genetic testing using blastocyst culture medium.

Hum Reprod 2019 07;34(7):1369-1379

Center of Reproductive Medicine, Shengjing Hospital of China Medical University, Huaxiang Road, Shenyang, China.

Study Question: Is minimally invasive chromosome screening (MICS) using blastocyst culture medium (BCM) sufficiently fast and accurate for preimplantation genetic testing (PGT).

Summary Answer: A new assay for MICS, named MICS-Inst achieved high-resolution, comprehensive chromosome ploidy detection using BCM.

What Is Known Already: BCM is a viable source of genomic DNA for use in PGT.

Study Design, Size, Duration: Forty-one vitrified blastocysts donated by 22 couples known to carry a chromosome rearrangement and 21 vitrified blastocysts donated from 8 couples with normal karyotypes were used in this study. Good-quality blastocysts, defined as Day 5 and Day 6 embryos ≥ BB (AA, AB, BA, BB) based on the Gardner system were used for analysis. Recruitment took place from May 2018 to August 2018. We performed PGT for structural rearrangements (PGT-SR) on 41 BCM, trophectoderm (TE) biopsy and blastocyst-stage embryo (BE) samples as well as PGT for aneuploidies (PGT-A) on 21 BCM, TE biopsy and BE samples.

Participants/materials, Setting, Methods: We made several significant modifications to the BCM composition (mixing blastocoel fluid and spent blastocyst medium) as well as the pre-existing multiple annealing and looping-based amplification cycles (MALBAC) techniques and library generation procedures. The design of a quasilinear preamplification (Pre-AMP) primer and AMP primers 1 and 2 enables the preparation of a next-generation sequencing library after the exponential amplification stage by introducing the Illumina P5 and P7 primers into the final products, which are then ready for sequencing. Sequencing was performed on the Illumina Hiseq 2500 platform with 2.0 Mb raw reads generated for each sample.

Main Results And The Role Of Chance: For PGT-A, BCM and TE biopsy samples showed 90% and 86% clinical concordance with the corresponding BE samples, respectively. In addition, both BCM and TE biopsy samples showed 76% karyotype concordance with the corresponding BE samples. For PGT-SR, we successfully obtained ploidy information for all 23 chromosomes with the exception of any rearrangements involving the Y chromosome. Both BCM and TE biopsy samples showed 100% clinical concordance with the corresponding BE samples in detecting chromosomal rearrangements. BCM and TE biopsy samples showed 90% and 100% karyotype concordance with the corresponding BE samples, respectively. Additionally, no statistically significant differences were detected in the aforementioned values of the BCM and TE biopsy samples in either PGT-A or PGT-SR (P > 0.05). Moreover, we achieved accurate quantification of segmental abnormalities using BCM samples. In addition, MICS-Inst reduced the number of steps required for library preparation through the use of new primer designs, resulting in an overall time reduction of 7.5 h. This time reduction allows for the performance of fresh blastocyst transfers.

Limitations, Reasons For Caution: The main limitation is that BE, rather the inner cell mass, was used as the standard to evaluate the chromosome screening results.

Wider Implications Of The Findings: These results show that MICS-Inst is effective in procedure and precision for PGT, and that it is possible to achieve fresh blastocyst transfer following PGT. The implications are significant, as these findings may lead to minimally invasive PGT methods in the future.

Study Funding/competing Interest(s): This work was supported by the National Natural Science Foundation of China (No. 81671423 and No. 81402130), the National Key Research and Development Program of China (No. 2018YFC1003100), Liaoning Provincial Key Research and Development Program (No. 2018225090), the Fok Ying Tung Education Foundation (No. 151039) and Distinguished Talent Program of Shengjing Hospital (No. ME76). No competing interests declared.
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July 2019

Preimplantation Genetic Screening with Spent Culture Medium/Blastocoel Fluid for in Vitro Fertilization.

Sci Rep 2018 06 18;8(1):9275. Epub 2018 Jun 18.

Jinxin Research Institute for Reproductive Medicine and Genetics, Chengdu Jinjiang Hospital for Maternal and Child Health Care, 66 Jingxiu Road, Chengdu, 610066, China.

Preimplantation genetic screening (PGS) detects chromosomal aneuploidy from DNA extracted from trophectodermal biopsy of the embryos before implantation. Although a controlled study showed no difference in pregnancy rates between this invasive cell biopsy technique and a non-biopsied control group, the potential long-term damage by the current PGS method has not be completely ruled out. We therefore tested a less-invasive protocol which utilizes spent culture medium combining with blastocoel fluid (ECB) to assess chromosomal aneuploidy. We compared the new protocol with the currently employed trophectodermal biopsy method against chromosomal information obtained from the remaining embryo. We found that the new technique generated information about aneuploidy that was not entirely identical to obtained from the biopsied trophectoderm or the remaining embryo. As the origins of the DNA extracted from the three sample types were not the same, the significance and interpretation of each result would have its own meaning. The possible implications derived from the ECB results as well as those from cell biopsy were discussed. The effectiveness of this new approach in selecting the best embryo for uterine implantation awaits further long term evaluation.
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June 2018

Reversine Increases the Plasticity of Long-Term Cryopreserved Fibroblasts to Multipotent Progenitor Cells through Activation of Oct4.

Int J Biol Sci 2016 1;12(1):53-62. Epub 2016 Jan 1.

1. Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China.

Reversine, a purine analog, had been evidenced that it could induce dedifferentiation of differentiated cells into multipotent progenitor cells. Here, we showed that reversine could increase the plasticity of long-term cryopreserved bovine fibroblasts, and reversine-treated cells achieved the ability to differentiate into all three germ layers cells, such as osteoblasts and adipocytes from mesoblast, neurocyte from ectoderm, hepatocytes and smooth muscle cells from endoderm. Moreover, treatment of reversine caused the grow arrest of fibroblasts at G2/M and distinct cell swelling resulting in the formation of polyploid cells. In parallel, reversine treatment induced a multipotency of fibroblasts might be attributed to the activation of histone modifications, especially the degression of DNA methylation. However, molecular and cellular experiments suggested that reversine treatment enhanced selectively the expression of pluripotent marker gene Oct4 and mesenchymal marker genes CD29, CD44 and CD73, but Sox2 and Nanog were not detected. Taken together, these results clearly demonstrate the ability of reversine to dedifferentiation of long-term cryopreserved somatic cells through activation of pluripotent gene Oct4.
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September 2016