Paternal Genome Elimination in Liposcelis Booklice (Insecta: Psocodea)
Paternal Genome Elimination in Liposcelis Booklice (Insecta: Psocodea)
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DOI：
10.1534/genetics.117.199786
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发表时间：
2017-06-01
期刊：
影响因子：
3.3
通讯作者：
Perlman, Steve J.
中科院分区：
文献类型：
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作者：
Hodson, Christina N.;Hamilton, Phineas T.;Perlman, Steve J.
昆虫的性别是如何决定的是多样的和动态的，包括雄性异配子、雌性异配子和单倍性。在许多昆虫谱系中，性别决定要么完全未知，要么研究不足。我们研究了Psocodea的性别决定，这是一种物种丰富的昆虫，包括寄生虱，barklice和书虱。我们专注于最近发现的一种Liposcelis booklice（Psocodea：Troctomorpha），这是寄生虱最接近的自由生活的亲戚。使用遗传学，基因组学和免疫组化方法，我们表明，这组表现出父系基因组消除（PGE），一种不寻常的性别决定模式，涉及基因组印记。控制杂交，在多代遗传标记之后，证明雄性只将他们从母亲那里继承的基因传递给后代。免疫荧光显微镜显示密集的chromocents与H3 K9 me 3-一个保守的标记异染色质，在男性，但不是在女性，这表明沉默的染色体在男性。在男性和女性文库中的基因组组装和读段覆盖率的比较显示没有分化的性染色体的证据。我们还发现，女性在生命早期产生更多的儿子，与兼性性别分配一致。PGE很可能广泛存在于Psocodea中，包括人类虱子。这一顺序代表了一个有前途的模型，研究这种神秘的性别决定模式。
How sex is determined in insects is diverse and dynamic, and includes male heterogamety, female heterogamety, and haplodiploidy. In many insect lineages, sex determination is either completely unknown or poorly studied. We studied sex determination in Psocodea-a species-rich order of insects that includes parasitic lice, barklice, and booklice. We focus on a recently discovered species of Liposcelis booklice (Psocodea: Troctomorpha), which are among the closest free-living relatives of parasitic lice. Using genetic, genomic, and immunohistochemical approaches, we show that this group exhibits paternal genome elimination (PGE), an unusual mode of sex determination that involves genomic imprinting. Controlled crosses, following a genetic marker over multiple generations, demonstrated that males only transmit to offspring genes they inherited from their mother. Immunofluorescence microscopy revealed densely packed chromocenters associated with H3K9me3-a conserved marker for heterochromatin-in males, but not in females, suggesting silencing of chromosomes in males. Genome assembly and comparison of read coverage in male and female libraries showed no evidence for differentiated sex chromosomes. We also found that females produce more sons early in life, consistent with facultative sex allocation. It is likely that PGE is widespread in Psocodea, including human lice. This order represents a promising model for studying this enigmatic mode of sex determination.