藻类基因组揭示了进化马赛克主义和核态生物的命运
Bruce A Curtis1, Goro Tanifuji, Fabien Burki
1Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
Nature
|December 4, 2012
概括
加密藻和甲基藻保留核形态,是内共生事件的剩余核. 基因组测序揭示了基因马赛克,并解释了为什么必需的基因仍然被锁定在这些独特的结构中.
科学领域:
- 单核细胞生物学 单核细胞生物学
- 内生共生研究研究内生共生.
- 藻类基因组学 藻类基因组学
背景情况:
- 加密藻和甲基藻是二次内生共生的模型.
- 这些藻类独特地保留了核形态体,即被吞没的藻类内共生体的剩余核.
- 了解核态生物的持久性是真核生物-真核生物内共生的关键.
研究的目的:
- 测序和分析吉拉尔迪亚甲 (密码植物) 和比格洛维埃拉纳坦斯 (chloroarachniophyte) 的核基因组.
- 调查核变体持久性的遗传基础和进化影响.
- 阐明这些复杂细胞中的基因转移动态和功能基因分布.
主要方法:
- 全基因组测序的吉拉迪亚甲和Bigelowiella natans.
- 遗传学分析以重建进化关系.
- 亚细胞向预测,以确定基因定位和功能.
主要成果:
- 这两种基因组都超过了21,000个蛋白质基因,并且具有丰富的内核.
- 比格洛维埃拉·纳坦斯 (Bigelowiella natans) 显示了广泛的替代拼接.
- 观察到广泛的遗传和生化马赛克,其中宿主和内生体基因为多个细胞区提供服务.
- 正在进行的线粒体到核的基因转移,但没有塑性质到核或核形态到核的转移.
结论:
- 缺少塑体和核型到核基因转移解释了核型体内基本基因的保留.
- 遗传和生化马赛克主义是这些二级内共生系统的标志.
- 这些发现为复杂的真核基因组的进化和维护提供了基本的见解.
相关概念视频
02:29Hybrid Zones
Hybrid zones are narrow regions where two closely related species interact, mate, and produce hybrids. Relative to either parent species, hybrids may possess distinct phenotypic or genetic differences that impact their survival and reproductive success. The genetic variances introduced by hybridization influence species diversity and speciation processes within the hybrid zone.
02:08Gene Conversion
Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...
01:21Nondisjunction
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This produces daughter cells with abnormal chromosome numbers. Nondisjunction is common during anaphase I or anaphase II of meiosis. Mutations in synaptonemal complex proteins that attach homologous chromosomes increase the chances of nondisjunction in anaphase I of meiosis I. In contrast, mutations in topoisomerases and condensins that hold sister...
01:28Overview of Algae
The kingdom Archaeplastida encompasses red and green algae, along with land plants. Unlike other protists with chloroplasts that arose through secondary endosymbiosis, only red and green algae originated from primary endosymbiotic events. This diverse group of eukaryotic organisms contains chlorophyll and performs oxygenic photosynthesis.Algae exist in various forms, from large brown kelp in coastal waters to green scum in puddles and stains on rocks or soil. Some species are responsible for...
01:23Red Algae
Red algae, also known as rhodophytes, are primarily found in marine environments, though some species inhabit freshwater and terrestrial ecosystems. These organisms exist in both unicellular and multicellular forms, with some multicellular varieties reaching macroscopic sizes.As phototrophic organisms, red algae contain chlorophyll a; however, their chloroplasts lack chlorophyll b. Instead, they possess phycobiliproteins, which serve as major light-harvesting pigments, similar to those found in...
01:27Diversity of Protists IV
Amoebozoa represent a diverse group of terrestrial and aquatic protists that utilize lobe-shaped pseudopodia for locomotion and feeding. This characteristic differentiates them from the Rhizaria, which possess threadlike pseudopodia. The primary classifications within Amoebozoa include gymnamoebas, entamoebas, and the plasmodial and cellular slime molds. Phylogenetic evidence indicates that Amoebozoa diverged from a lineage that ultimately gave rise to fungi and animals.Gymnamoebas and...