Background Wool fibers are valuable materials for textile industry.Typical wool fibers are divided into medullated and non-medullated types,with the former generated from primary wool follicles and the latter by eithe...Background Wool fibers are valuable materials for textile industry.Typical wool fibers are divided into medullated and non-medullated types,with the former generated from primary wool follicles and the latter by either primary or secondary wool follicles.The medullated wool is a common wool type in the ancestors of fine wool sheep before breeding.The fine wool sheep have a non-medullated coat.However,the critical period determining the type of wool follicles is the embryonic stage,which limits the phenotypic observation and variant contrast,making both selection and studies of wool type variation fairly difficult.Results During the breeding of a modern fine(MF)wool sheep population with multiple-ovulation and embryo transfer technique,we serendipitously discovered lambs with ancestral-like coarse(ALC)wool.Whole-genome rese-quencing confirmed ALC wool lambs as a variant type from the MF wool population.We mapped the significantly associated methylation locus on chromosome 4 by using whole genome bisulfite sequencing signals,and in turn identified the SOSTDC1 gene as exons hypermethylated in ALC wool lambs compare to their half/full sibling MF wool lambs.Transcriptome sequencing found that SOSTDC1 was expressed dozens of times more in ALC wool lamb skin than that of MF and was at the top of all differentially expressed genes.An analogy with the transcriptome of coarse/fine wool breeds revealed that differentially expressed genes and enriched pathways at postnatal lamb stage in ALC/MF were highly similar to those at the embryonic stage in the former.Further experiments validated that the SOSTDC1 gene was specifically highly expressed in the nucleus of the dermal papilla of primary wool follicles.Conclusion In this study,we conducted genome-wide differential methylation site association analysis on differen-tial wool type trait,and located the only CpG locus that strongly associated with primary wool follicle development.Combined with transcriptome analysis,SOSTDC1 was identified as the only gene at this locus that was specifically overexpressed in the primary wool follicle stem cells of ALC wool lamb skin.The discovery of this key gene and its epigenetic regulation contributes to understanding the domestication and breeding of fine wool sheep.展开更多
基金the programs of National Key R&D Program of China(2021YFF1000700)National Natural Science Foundation of China(32002145)+1 种基金the Major Project for Cultivation Technology of New Varieties of Genetically Modified Organisms of the Ministry of Agriculture(grant Nos.2016ZX08008-001 and 2013ZX08008-001)Ningxia Agricultural Breeding Project(NXNYYZ2015010).
文摘Background Wool fibers are valuable materials for textile industry.Typical wool fibers are divided into medullated and non-medullated types,with the former generated from primary wool follicles and the latter by either primary or secondary wool follicles.The medullated wool is a common wool type in the ancestors of fine wool sheep before breeding.The fine wool sheep have a non-medullated coat.However,the critical period determining the type of wool follicles is the embryonic stage,which limits the phenotypic observation and variant contrast,making both selection and studies of wool type variation fairly difficult.Results During the breeding of a modern fine(MF)wool sheep population with multiple-ovulation and embryo transfer technique,we serendipitously discovered lambs with ancestral-like coarse(ALC)wool.Whole-genome rese-quencing confirmed ALC wool lambs as a variant type from the MF wool population.We mapped the significantly associated methylation locus on chromosome 4 by using whole genome bisulfite sequencing signals,and in turn identified the SOSTDC1 gene as exons hypermethylated in ALC wool lambs compare to their half/full sibling MF wool lambs.Transcriptome sequencing found that SOSTDC1 was expressed dozens of times more in ALC wool lamb skin than that of MF and was at the top of all differentially expressed genes.An analogy with the transcriptome of coarse/fine wool breeds revealed that differentially expressed genes and enriched pathways at postnatal lamb stage in ALC/MF were highly similar to those at the embryonic stage in the former.Further experiments validated that the SOSTDC1 gene was specifically highly expressed in the nucleus of the dermal papilla of primary wool follicles.Conclusion In this study,we conducted genome-wide differential methylation site association analysis on differen-tial wool type trait,and located the only CpG locus that strongly associated with primary wool follicle development.Combined with transcriptome analysis,SOSTDC1 was identified as the only gene at this locus that was specifically overexpressed in the primary wool follicle stem cells of ALC wool lamb skin.The discovery of this key gene and its epigenetic regulation contributes to understanding the domestication and breeding of fine wool sheep.
