カンブリア低期のロボポディアンカーディオディクティオンは,ユーアルトポッドの脳起源を決定する
Nicholas J Strausfeld1, Xianguang Hou2, Marcel E Sayre3,4
1Department of Neuroscience, University of Arizona, Tucson, AZ, USA.
Science (New York, N.Y.)
|November 24, 2022
まとめ
lobopodian Cardiodictyon catenulumの化石化した神経系は,分割されていない頭と脳を明らかにします. この発見は,関節足類の頭部進化を明らかにし,ユーアートロポッドの頭部進化を先行した.
科学分野:
- 古生物学
- 進化生物学
- 神経科学
背景:
- 節足類の頭と脳の起源と進化はよくわかっていないが,異なった形質学と系統学的関係が統一的な説明に挑戦している.
- これらの違いを調和させることは 進化生物学の長年の課題です
研究 の 目的:
- 節足類の頭と脳の進化史を明らかにする
- 節足類で観察される多様な形態と系統学的関係について,統一的な根拠を提供すること.
主な方法:
- カンブリア低層のロボポディアの神経系化石の分析
- 幹群関節足類との頭部領域の比較形態学
- ホモログな遺伝子発現パターンを,現存するパナートロポッドと一致させる.
主要な成果:
- カーディオディクティオン・カタネルムの化石化した神経系は,3つの異なる頭部領域を持つ未分割の頭と脳を示している.
- これらの領域は,幹部に奉仕するメタメリック腹部神経系とは分離しています.
- 各頭部領域は前腸の構成部分と 頭部付属体に合わせています
- 形態学的対応と遺伝子発現パターンは,これらの頭部領域がユーアトロポッドの頭部進化に先立つことを示している.
結論:
- カーディオディクティオン・キャテヌラムの頭部領域は,ユーアートロポッドの頭部の前駆体である.
- これらのドメインは,現存するケリセラトとマンディブラトの脳に存在するニューロメアに対応する.
- この発見は 節足類の頭と脳の進化について 統一的な見方を示しています
関連する概念動画
01:22Lobes of the Cerebrum
844
The cerebral cortex, a critical structure of the brain, is intricately divided into two hemispheres, each consisting of four distinct lobes: occipital, temporal, frontal, and parietal. These lobes function cooperatively to regulate various cognitive and sensory functions, forming the basis of our complex neural capabilities.
Frontal lobe
The frontal lobes, located behind the forehead, are the command center of our brain, controlling personality, intelligence, and voluntary muscle movements....
Frontal lobe
The frontal lobes, located behind the forehead, are the command center of our brain, controlling personality, intelligence, and voluntary muscle movements....
844
01:54Convergent Evolution
28.2K
Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.
28.2K
02:40The Tree of Life - Bacteria, Archaea, Eukaryotes
32.9K
The “tree of life” describes the evolution of life and the evolutionary relationships between organisms. The root of the tree is the common ancestor to all life on Earth. All other species radiate from this point, much like the branches of a tree. The numerous tips of these branches on the tree of life represent every living, or extant, species. Extinct species, which are species that no longer exist, can be found towards the center of the tree. Currently, these organisms, both...
32.9K
01:11Cerebrum: Anatomical Overview II
2.2K
Each cerebral hemisphere can be divided into three main regions. The outermost region, the cerebral cortex, is a thin layer (2 to 4 millimeters thick) made up of gray matter, consisting of neuron cell bodies, dendrites, glial cells, and blood vessels. The middle region, or white matter, is primarily composed of myelinated nerve fibers organized into three types of large tracts: association fibers, commissures, and projection fibers. Association fibers connect different areas within the same...
2.2K
01:30Neurulation
42.2K
Neurulation is the embryological process which forms the precursors of the central nervous system and occurs after gastrulation has established the three primary cell layers of the embryo: ectoderm, mesoderm, and endoderm. In humans, the majority of this system is formed via primary neurulation, in which the central portion of the ectoderm—originally appearing as a flat sheet of cells—folds upwards and inwards, sealing off to form a hollow neural tube. As development proceeds, the...
42.2K
01:27Cranial Bones: Lateral View
2.4K
The lateral view of the cranium is dominated by temporal, sphenoid, and ethmoid bones.
The temporal bone forms the lower lateral side of the skull. The temporal bone is subdivided into several regions. The flattened upper portion is the squamous portion of the temporal bone. Below this area and projecting anteriorly is the zygomatic process of the temporal bone, which forms the posterior portion of the zygomatic arch. Posteriorly is the mastoid portion of the temporal bone. Projecting...
The temporal bone forms the lower lateral side of the skull. The temporal bone is subdivided into several regions. The flattened upper portion is the squamous portion of the temporal bone. Below this area and projecting anteriorly is the zygomatic process of the temporal bone, which forms the posterior portion of the zygomatic arch. Posteriorly is the mastoid portion of the temporal bone. Projecting...
2.4K