Aslam Muhammad Aamir, Schokker Dirkjan, Groothuis Ton G G, de Wit Agnes A C, Smits Mari A, Woelders Henri
Animal Breeding and Genomics Centre, Wageningen UR Livestock Research, Lelystad, The Netherlands.
Behavioural Biology, Centre for Behaviour and Neuroscience, University of Groningen, AG Groningen, The Netherlands.
Biol Reprod. 2015 Jun;92(6):157. doi: 10.1095/biolreprod.114.123380. Epub 2015 May 13.
Female birds have been shown to manipulate offspring sex ratio. However, mechanisms of sex ratio bias are not well understood. Reduced feed availability and change in body condition can affect the mass of eggs in birds that could lead to a skew in sex ratio. We employed feed restriction in laying chickens (Gallus gallus) to induce a decrease in body condition and egg mass using 45 chicken hens in treatment and control groups. Feed restriction led to an overall decline of egg mass. In the second period of treatment (Days 9-18) with more severe feed restriction and a steeper decline of egg mass, the sex ratio per hen (proportion of male eggs) had a significant negative association with mean egg mass per hen. Based on this association, two groups of hens were selected from feed restriction group, that is, hens producing male bias with low egg mass and hens producing female bias with high egg mass with overall sex ratios of 0.71 and 0.44 respectively. Genomewide transcriptome analysis on the germinal disks of F1 preovulatory follicles collected at the time of occurrence of meiosis-I was performed. We did not find significantly differentially expressed genes in these two groups of hens. However, gene set enrichment analysis showed that a number of cellular processes related to cell cycle progression, mitotic/meiotic apparatus, and chromosomal movement were enriched in female-biased hens or high mean egg mass as compared with male-biased hens or low mean egg mass. The differentially expressed gene sets may be involved in meiotic drive regulating sex ratio in the chicken.
已有研究表明雌性鸟类能够操控后代的性别比例。然而,性别比例偏差的机制尚未得到充分理解。饲料供应减少和身体状况的变化会影响鸟类的蛋重,进而可能导致性别比例失衡。我们对蛋鸡(原鸡)实施限饲,通过45只母鸡分为处理组和对照组,诱导其身体状况和蛋重下降。限饲导致蛋重总体下降。在处理的第二阶段(第9 - 18天),限饲更为严格,蛋重下降更为明显,每只母鸡的性别比例(雄性蛋的比例)与每只母鸡的平均蛋重呈显著负相关。基于这种关联,从限饲组中挑选出两组母鸡,即产雄性偏多且蛋重低的母鸡和产雌性偏多且蛋重高的母鸡,其总体性别比例分别为0.71和0.44。对减数分裂I发生时收集的F1排卵前卵泡的胚盘进行全基因组转录组分析。我们在这两组母鸡中未发现显著差异表达的基因。然而,基因集富集分析表明,与细胞周期进程、有丝分裂/减数分裂装置和染色体运动相关的一些细胞过程在雌性偏多的母鸡或平均蛋重高的母鸡中比在雄性偏多的母鸡或平均蛋重低的母鸡中更富集。差异表达的基因集可能参与了鸡性别比例的减数分裂驱动调控。