Copy number variation of MYLK4 gene and its growth traits of Capra hircus (goat).

Copy number variation (CNV) is a form of genetic variation caused by genome rearrangement, with abnormal fragments ranging from 50 bp to Mb. And, CNV is closely related to disease, growth and reproductive shape of livestock. As a member of myosin light chain kinase (MYLK) family with serine/threonine specificity, MYLK4 belongs to an enzyme encoded by MYLK4 gene. Although MYLK4 is a recognized kinase, its function has yet to be revealed in subsequent studies. This study aims to analyze CNV and genetic effects of MYLK4 gene in goats. We used qPCR to detect CNV of MYLK4 gene in African Nubian goat (n = 32), Guizhou black goat (n = 196) and Guizhou white goat (n = 95), respectively, and correlated CNV data of MYLK4 gene with goat growth traits in Chinese goats. The results showed that the effect of MYLK4 gene CNV on body weight, body length and body height of goats had significantly different (p < 0.05, Q < 0.05), in which CNV showed better growth traits in type of deletion. Therefore, CNV of MYLK4 gene can be used as a molecular marker for assisted selection of goat growth traits, which provides a theoretical basis for the genetic improvement of goat breeds in China.

[Effect of intact donor cell membrane and cytoplasm of cumulus on development of mouse somatic clones in vitro].

Reconstructed embryos can be got by two nuclear transfer methods, fusion and microinjection. However, the fusion method is time-taking and has low efficiency. Microinjection involved the donor nucleus isolation, which may lead to the damage of the nucleus DNA. Cloning efficiency may be reduced by low fusion rate of the cell fusion method and damaged DNA of microinjection method. So some researchers used the intracytoplasmic injection of the whole-cell donor, which was simple and less labor-intensive for cloning study. Here we used the intact cumulus cell as donor to study the feasibility of the microinjection method in mouse nuclear transfer. After the whole cell injection of the cumulus, most of the couplets were fragmented following activation at 1 or 6 h after injection. Whereas those only the nucleus after isolation from the cumulus was injected cleaved and developed normally. The control group of oocytes, which were not injected with the donor, was also fragmented after enucleation. Most of the couplets of the parthenotes after intact cumulus cell injection were fragmented. The group of those in which the donor was just broken and then injected (nucleus with most of the broken membrane and the cytoplasm were injected) developed as a lower rate compared to those only isolated nucleus being injected. These results suggest that the intact donor membrane of cumulus cell hinder the reprogramming of oocyte for somatic nucleus and components of donor cytoplasm and membrane affected the development of the clones in vitro.