近期,，中國(guó)農(nóng)業(yè)大學(xué)動(dòng)物科技學(xué)院研究者近期在PLOS Genetics發(fā)表了"An EAV-HP Insertion in 5' Flanking Region of SLCO1B3 Causes Blue Eggshell in the Chicken"一文,，揭示了綠殼雞蛋形成的遺傳機(jī)制。
雞蛋殼之所以會(huì)呈現(xiàn)綠色,，是由于蛋殼中沉積了較多的膽綠素,。我國(guó)的地方雞品種中，有一些具有產(chǎn)綠殼蛋的特性,，后經(jīng)過(guò)選育形成了東鄉(xiāng)綠殼蛋雞,，盧氏綠殼蛋雞等品種。至于雞蛋為綠殼的遺傳機(jī)制一直未被人們所理解,。
中國(guó)農(nóng)業(yè)大學(xué)的研究者以中國(guó)的綠殼蛋雞為實(shí)驗(yàn)材料,，發(fā)現(xiàn)母雞1號(hào)染色體的SLCO1B3基因啟動(dòng)子區(qū)域存在EAV-HP的插入，使得SLCO1B3基因在母雞的卵殼腺中特異表達(dá),，因而導(dǎo)致母雞產(chǎn)綠殼蛋,。EVA-HP為一種鳥類的逆轉(zhuǎn)率病毒，廣泛存在鳥類的基因組中,，而非產(chǎn)綠殼蛋的母雞的SLCO1B3基因由于不含EAV-HP插入而不表達(dá)。SLCO1B3基因?qū)儆谟袡C(jī)陰離子轉(zhuǎn)運(yùn)蛋白（OATP）家族,，能幫助膽鹽類的跨膜運(yùn)輸至卵殼腺,，卵殼腺將膽綠素分泌至蛋殼中，使得最終的蛋殼呈現(xiàn)綠色,。
南美安克拉雞也具有產(chǎn)綠殼蛋的性狀,，研究發(fā)現(xiàn)其與中國(guó)的綠殼蛋雞相比，EVA-HP在SLCO1B3插入位置略有差異,，可能是因?yàn)樵撏蛔冊(cè)趦傻鼐G殼蛋雞進(jìn)化中為獨(dú)立的事件,。研究控制蛋殼綠色基因也為研究家雞進(jìn)化提供了一些素材。（生物谷Bioon.com）
doi:10.1371/journal.pgen.1003183
An EAV-HP Insertion in 5′ Flanking Region of SLCO1B3 Causes Blue Eggshell in the Chicken.
Wang Z, Qu L, Yao J, Yang X, Li G, et al.
The genetic determination of eggshell coloration has not been determined in birds. Here we report that the blue eggshell is caused by an EAV-HP insertion that promotes the expression ofSLCO1B3 gene in the uterus (shell gland) of the oviduct in chicken. In this study, the genetic map location of the blue eggshell gene was refined by linkage analysis in an F2 chicken population, and four candidate genes within the refined interval were subsequently tested for their expression levels in the shell gland of the uterus from blue-shelled and non-blue-shelled hens. SLCO1B3 gene was found to be the only one expressed in the uterus of blue-shelled hens but not in that of non-blue-shelled hens. Results from a pyrosequencing analysis showed that only the allele of SLCO1B3 from blue-shelled chickens was expressed in the uterus of heterozygous hens (O*LC/O*N). SLCO1B3 gene belongs to the organic anion transporting polypeptide (OATP) family; and the OATPs, functioning as membrane transporters, have been reported for the transportation of amphipathic organic compounds, including bile salt in mammals. We subsequently resequenced the whole genomic region of SLCO1B3 and discovered an EAV-HP insertion in the 5′ flanking region of SLCO1B3. The EAV-HP insertion was found closely associated with blue eggshell phenotype following complete Mendelian segregation. In situ hybridization also demonstrated that the blue eggshell is associated with ectopic expression of SLCO1B3 in shell glands of uterus. Our finding strongly suggests that the EAV-HP insertion is the causative mutation for the blue eggshell phenotype. The insertion was also found in another Chinese blue-shelled breed and an American blue-shelled breed. In addition, we found that the insertion site in the blue-shelled chickens from Araucana is different from that in Chinese breeds, which implied independent integration events in the blue-shelled chickens from the two continents, providing a parallel evolutionary example at the molecular level.
