Last eukaryotic common ancestor mitochondria Though current data indicate that the last eukaryote common ancestor possessed mitochondria and was a complex cell, whether Eventually, she hopes to enumerate a set of proteins that were the ancestors of the proteins that performed all of the cellular functions in the Last Common Ancestor. 2014), all three known types of eukaryotic energy metabolism were acquired from eubacteria and (3) that the free-living common ancestor of hydrogenosomes and mitochondria was capable of Eukaryotes compartmentalize their genetic material into a nucleus, are contained within a structurally complex cytoskeleton, and all have mitochondria or an organelle of Modern forms of eukaryotes that inhabit Earth today include fungi, plants, animals and single-celled organisms such as amoebae. This includes endomembranes (in particular, the nuclear compartment), a complex cytoskeleton Also, recall that all extant eukaryotes descended from an ancestor with mitochondria. Horizontal gene transfer. The biosphere in which LUCA and contemporaries were living was FECA, first eukaryotic common ancestor; FMCA, first mitochondrial common ancestor; LECA, last eukaryotic common ancestor. The five eukaryotic supergroups—Excavates, Rhizaria, Unikonts, Chromalveolates, and Plantae—are shown to diverge directly from the last common ancestor (black circle) The Aristotle scenarios. endosymbiosis d. LECA was A notable problem with any model proposing such an early origin of the eukaryotes is the observation that the Last Eukaryotic Common Ancestor (LECA) possessed a lineage (also called first eukaryotic common ancestor, or FECA) to the LECA is effectively an event horizon (Je´kely 2005); although gene duplications can be traced across this horizon The functional period of eukaryogenesis started just prior to the symbiosis between two prokaryotes and ended when the last common ancestor of modern eukaryotes arose. Increasing amounts of data These essential functions of mitochondria are conserved across all eukaryotic groups, tracing the backbone of eukaryotic cell biology to the mitochondria of the last eukaryotic common ancestor (LECA) . 2018; Javaux and Lepot 2018). Increasing amounts of data enable such But the bacterial origin of mitochondria and their presence in the eukaryote common ancestor [44–47], together with the tendency of eukaryotes to branch within archaeal Most intuitive of these landmarks is the last eukaryotic common ancestor (LECA) (Makarova et al. Given the coincidence of mitochondria with the eukaryotic state, this can also be seen as a Endosymbiotic events probably contributed to the origin of the last common ancestor (LCA) of today’s eukaryotes. For the purposes of this example, we will assume that LECA . common ancestor of all extant Study with Quizlet and memorize flashcards containing terms like What event is thought to have contributed to the evolution of eukaryotes?, Which characteristic is shared by prokaryotes and This imposes a minimal age for the origin of eukaryotes that roughly agrees with the oldest boundaries of recent molecular dating estimates for the last eukaryotic common ancestor (LECA; 1. The single presumed example is the endosymbiogenetic origin of mitochondria, which is hidden behind Insight into the Last Eukaryotic Common Ancestor (LECA) is central to any phylogeny-based reconstruction of early eukaryotic evolution. It possessed bacterial lipids, nuclei, sex, an The origin of eukaryotes is one of the hardest problems in evolutionary biology and sometimes raises the ominous specter of irreducible complexity. All living organisms are derived from LECA. Though current data indicate that the last eukaryote common ancestor Study with Quizlet and memorize flashcards containing terms like What event is thought to have contributed to the evolution of eukaryotes? a. LUCA and LECA were sophisticated cells. (a) The traditional ladder-like evolutionary scenario, in which organisms increased in complexity from the origin of life to prokaryotes and eukaryotes, Other studies have shown that the ancestral mitochondrial ribosome in the last eukaryotic common ancestor was already much larger than its bacterial ancestor, containing some 19 Nucleus first, followed by internal membranes, and mitochondria last. Many We employed a novel phylogenomic test that summarizes ASR across trees which reconstructs a last eukaryotic common ancestor that possessed mitochondria, was Comparative genomics has revealed that the last eukaryotic common ancestor possessed the hallmark cellular architecture of modern eukaryotes. Nowadays, eukaryotic cells have 3 Although the chloroplast evolved only one time in the plant lineage, there are many lineages of microbial eukaryotes that have chloroplasts but are not plants. However, the remarkable The last eukaryotic common ancestors (LECAs) have extant archaeprotist descendants: motile nucleated cells with Embden-Meyerhof glycolysis and substrate-level phosphorylation that lack the α-proteobacterial We develop a symbiogenetic concept of the origin of eukaryotic intracellular motility systems from anaerobic but aerotolerant spiro-chetes in sulfide-rich environments. This ancestral organism is believed to have existed around Other studies have shown that the ancestral mitochondrial ribosome in the last eukaryotic common ancestor was already much larger than its bacterial ancestor, containing some 19 Eukaryotic predation has been invoked to explain a number of events in the Neoproterozoic, from the Rise of Algae to the origin of animals [33,34,60,66–68]. The transition from prokaryote to eukaryote has remained a One of these functions is to generate clusters of iron and sulfur that are important cofactors of many enzymes. One of the major features distinguishing prokaryotes from The formative stages of eukaryotic evolution can potentially be tracked back through these earlier times, converging not only on the last eukaryotic common ancestor (LECA), but also its assembly in an underlying Such organisms would be among the extinct precursors of the last common ancestor of eukaryotes. Therefore, most Full-fledged mitochondria were present in the last eukaryotic common ancestor (LECA), and are descended from bacterial endosymbionts related to alphaproteobacteria 1, The mitoribosome of the last eukaryotic common ancestor (LECA), after the establishment of the proto-mitochondrion, had an α-proteobacterial core consisting of 20 SSU Abstract. For the purposes of this example, we will assume sleeping sickness, Chagas disease, and leishmaniasis among Nous voudrions effectuer une description ici mais le site que vous consultez ne nous en laisse pas la possibilité. Reconstruction of the gene “If you try and look at all of the features that are commonly shared by many eukaryotes today, and you try to reconstruct which features should have been present in the Mitochondria: Most extant eukaryotes have “typical” mitochondria, although some eukaryotes have very reduced mitochondrial “remnants” and a few lack detectable mitochondria. Study with Quizlet and memorize flashcards containing terms like What event is thought to have contributed to the evolution of eukaryotes? global warming glaciation volcanic First eukaryal common ancestor, i. There is evidence that it could have lived a somewhat 'alien' lifestyle, Figure 1 shows some major structural changes between a typical prokaryotic cell, the first eukaryotic common ancestor, and the last eukaryotic common ancestor. Models of a prokaryote, first eukaryotic common ancestor, and last eukaryotic common ancestor. What traits would you find in the last common SUMMARY. Cells with mitochondria were able to utilize metabolic energy more efficiently. 8 to 1 Ga (Eme et al. Substantial transfer of genes from the ancestral proto The origin of eukaryotes has been defined as the major evolutionary transition since the origin of life itself. Proto-mitochondria Further, there remains debate concerning the precise mechanisms behind eukaryogenesis, i. Reconstruction of the most recent ancestor of all modern Endosymbiosis and organellogenesis are virtually unknown among prokaryotes. The origin of eukaryotes is a fundamental, forbidding evolutionary puzzle. Model showing the stepwise evolution of eukaryotic cell organization from (A) an eocyte ancestor with a single The last eukaryotic common ancestor (LECA) already had the intracellular organisation and gene repertoire characteristic of present-day eukaryotes 3, making the transition from prokaryotes to The last eukaryotic common ancestor has traits which are also found in bacterial and archaeal lineages, connecting them evolutionarily. FECA (First Eukaryotic Common Ancestor) designates the first organism or species In summary, arguments favoring a compartmentalized LUCA are as follows: 1) a eukaryote promoter system favors evolutionary rearrangements [46]; 2) it is known from Regardless of what the primordial mitochondrion was or was not capable of, gene inventory studies paint a very clear picture of what the last eukaryotic common ancestor was last universal common ancestor (LUCA), microorganism proposed to be the genetic ancestor of all domains of life—namely, the Bacteria, Archaea, and Eukarya. The idea The host's dependence upon molecular hydrogen produced by the symbiont is put forward as the selective principle that forged the common ancestor of eukaryotic cells. The last eukaryotic Most significantly, the two-domain model may imply that potentially more sophisticated and non-universal archaeal features were present in the ancestral lineage of the last eukaryotic The last eukaryote common ancestor (LECA) possessed mitochondria and all key traits that make eukaryotic cells more complex than their prokaryotic ancestors, yet the timing The last eukaryotic common ancestor (LECA): Acquisition of cytoskeletal motility from aerotolerant spirochetes in the Proterozoic Eon Many, if not all eubacterial enzymes One of the most significant events in the evolution of life is the origin of the eukaryotic cell, an increase in cellular complexity that occurred approximately 2 billion years ago. Which of the following observations Until recently, these protists were believed to lack mitochondria. The idea Question: Figure 1 shows some major structural changes between a typical prokaryotic cell, the first eukaryotic common ancestor, and the last eukaryotic common ancestor AWD Prokaryote The host's dependence upon molecular hydrogen produced by the symbiont is put forward as the selective principle that forged the common ancestor of eukaryotic cells. To gain insight into LECA Mitochondria most likely evolved by _____. a photosynthetic cyanobacterium b. Eukaryotic cells may contain anywhere from one to several thousand Such organisms would be among the extinct precursors of the last common ancestor of eukaryotes. Our earliest prokaryotic ancestors were probably _____, which ingested a small _____, eventually giving rise to the Last Eukaryotic Common Ancestor A. What must really be meant by this is that there was but one last eukaryotic common ancestor (LECA) from which all Study with Quizlet and memorize flashcards containing terms like What event is thought to have contributed to the evolution of eukaryotes? a. Instead of a Mitochondria are the energy powerhouses in eukaryotic cells. Although most biologists accept that the last common It is often said that eukaryotes arose only once. last universal common ancestor (LUCA), microorganism proposed to be the genetic ancestor of all domains of life—namely, the Bacteria, Archaea, and Eukarya. Most hallmark traits of eukaryotes, such as their intricate intracellular organization, All living plant and animal species today have their origins in the Last Eukaryotic Common Ancestor or LECA. Ancestral State Reconstructions Trace Mitochondria But Not Phagocytosis to the Last Eukaryotic Common Ancestor Genome Biol Evol. Mitochondrial remnant organelles, called mitosomes, Describe two ways in which paramecium differs from the Phylogenetic studies incorporating divergence times of major modern eukaryote groups predict the origin of stem-group eukaryotes broadly from 1. , Comparative genomics has revealed that the last eukaryotic common ancestor possessed the hallmark cellular architecture of modern eukaryotes. Comparative genomic analysis clearly shows that the last eukaryotic common ancestor (LECA) possessed Phylogenomics of eukaryote supergroups suggest a highly complex last common ancestor of eukaryotes and a key role of mitochondrial endosymbiosis in the origin of Eukaryotic lineage was established from the merger of an archaeal host with a α-proteobacterium, giving rise to the First Eukaryote Common Ancestor (FECA) 33. The oxidative phosphorylation system a prokaryote-like starting point to the first eukaryotic common ancestor (FECA); (ii) transition from the FECA to the last eukaryotic common ancestor (LECA); and (iii) evolution and divergence Inside-out model for the evolution of eukaryotic cell organization. Current evidence indicates that the Last Eukaryotic Common Ancestor (LECA) already possessed many All current theories for the origin of eukaryotes entail in some manner the concept of symbiogenesis (Mereschkowsky 1910; english translation in Kowallik and Martin 2021) All extant eukaryotes descend from the last eukaryotic common ancestor (LECA), which is thought to have featured complex cellular organization. Which of the following observations All current eukaryotic cells are believed to originate from one of these early cell lineages, which is referred to as LECA (Last Eukaryotic Common Ancestor). This is the 3D model. Although most biologists accept that the last common What is likely true of the last eukaryotic common ancestor?LECA was probably single-celled with both mitochondria and a flagellum. “Last Many scientists agree that eukaryotes have one common ancestor termed, Last Eukaryotic Common Ancestor (LECA). Although these organelles harbor their own genome, the large majority of genes, originally encoded in the endosymbiont, were either lost or transferred to the A new mitochondrial genome is the most gene-rich one found in a major division of eukaryotes — and it shares remarkable features with that of one of its most distant relatives. 8 billion years ago 9, but no life forms have been found that represent an That hundreds of species of anaerobic eukaryotes lost mitochondria on return to anoxic habitats and/or that all eukaryotic lineages began with hydrogenosome-mitochondrial ancestry is more assumption than conclusion based on In eukaryotic cells, mitochondria originated in an α-proteobacterial endosymbiont. Humans and all other nucleated creatures can trace their Mitochondria: Most extant eukaryotes have "typical" mitochondria, about eukaryotes’ cell walls and their development to know how much homology exists between those of prokaryotes and LECA refers to the last eukaryotic common ancestor. Mitochondria provide energy for larger cell size, Mitochondria: Most extant eukaryotes have “typical” mitochondria, although some eukaryotes have very reduced mitochondrial “remnants” and a few lack detectable mitochondria. e. patří k LUCA/FECA/LECA? FECA - poslední společný předek všech Question: Which abilities/characteristics are thought to have been possessed by LECA (last eukaryotic common ancestor) but NOT by FECA (first eukaryotic common ancestor)? (Select Mitochondria: Most extant eukaryotes have "typical" mitochondria, although some eukaryotes have very reduced mitochondrial “remnants” and a few lack detectable mitochondria. Ground-breaking research has centered In the last few decades, investigations of diverse eukaryotes have clarified the nature of the last eukaryotic common ancestor (LECA), the ‘endpoint’ of eukaryogenesis The latest Virtual Issue from Genome Biology and Evolution highlights articles that provide new insight into the deep evolutionary relationships among extant organisms and the The place of eukaryotes in the tree of life and the very origin of this domain remains one of the most intriguing issues in evolution and is subject of lively debate (Gribaldo et al. However, the remarkable The last eukaryotic common ancestor (LECA): Acquisition of cytoskeletal motility from aerotolerant spirochetes in the Proterozoic Eon itively lacked mitochondria" and "the That hundreds of species of anaerobic eukaryotes lost mitochondria on return to anoxic habitats and/or that all eukaryotic lineages began with hydrogenosome-mitochondrial Most significantly, the two-domain model may imply that potentially more sophisticated and non-universal archaeal features were present in the ancestral lineage of the last eukaryotic The earliest ancestor of mitochondria (that is not also an ancestor of an extant alphaproteobacterium) is the pre-mitochondrial alphaproteobacterium. b, Phylogenetic placement of eukaryotes Such a major transition cannot be selectively neutral: thousands of positive mutations must have been selected for, leading to the complex eukaryotic cell that the last Here, we have reconstructed the composition of the ancestral mitochondrial ribosome in the Last Eukaryotic Common Ancestor (LECA) and investigated its subsequent evolution in six major Assuming this is correct, the mitochondrial endosymbiosis must have happened prior to LECA but it must be younger than the last common ancestor of the eukaryote nucleocytoplasmic lineage Endosymbiosis and organellogenesis are virtually unknown among prokaryotes. At the same Abstract. Some extant eukaryotes have very reduced remnants of mitochondria in their cells, whereas other members of their lineages have “typical” mitochondria. Anaerobic heterotrophs; aerobic The oldest undisputedly eukaryotic microfossils go back 1. The single presumed example is the endosymbiogenetic origin of mitochondria, which is hidden behind the event horizon of the last eukaryotic Abstract. In the tree on the right, LECA appeared from a branch of an archaea group. volcanic activity A growing bacteria or archaea can take in genes from the environment around them by ‘recombining’ new genes into their DNA strand. cytoskeletal elements c. Mitochondria arise only from previous mitochondria; they are not formed from scratch (de MORE Mitochondria,originated from the last eukaryotic common ancestor by endosymbiosis,are semi-autonomous double-membrane organelles. c endosymbiosis Which of the There is little doubt that EGT and gene loss have extensively shaped the genomes of modern eukaryotes: while mitochondria often contain more than 1,000 proteins, very few are All eukaryotic cells have mitochondria, but not all eukaryotic cells have chloroplasts. Although most eukaryotes have mitochondria, They maintained that the common ancestor of all living eukaryotes already carried an endosymbiont. All eukaryotes have mitochondria. This In the last few decades, investigations of diverse eukaryotes have clarified the nature of the last eukaryotic common ancestor (LECA), the ‘endpoint’ of eukaryogenesis Around 4 billion years ago there lived a microbe called LUCA: the Last Universal Common Ancestor. 6 Ba (Betts et al. 0–1. Figure \(\PageIndex{1}\): Endosymbiosis: Modern eukaryotic cells evolved In 2016, scientists published the genome of Monocercomonoides, and demonstrated that this organism has no detectable mitochondrial genes. The origin of eukaryotic cell complexity Eventually, all the common traits of extant eukaryotes would be acquired, yielding an organism researchers refer to as LECA, or the last eukaryotic common ancestor. "The most recent common ancestor from which all eukaryotes descended is termed the last eukaryotic common ancestor or LECA. LECA refers to the last eukaryotic common ancestor. R. The transition from prokaryote to eukaryote has remained a For example, we estimate that the last common ancestor of extant mitochondria (and therefore of extant eukaryotes) lived 1880 to 1502 million years ago (Ma). volcanic activity In the tree on the left, eukaryote emerged from a common ancestor shared with archaea. The last eukaryote common ancestor (LECA) possessed mitochondria and all key traits that make eukaryotic cells more complex than their prokaryotic ancestors, yet the timing Insight into the last eukaryotic common ancestor (LECA) is central to any phylogeny-based reconstruction of early eukaryotic evolution. Last eukaryal common ancestor, i. These organelles were first observed by light microscopists in the late 1800s, where they were worm The transition from pro- to eukaryote evolution is poorly understood due to a lack of reliable intermediate forms and definitions regarding the nature of the first host that could no Arguments based on cell energetics favour the view that a mitochondrion capable of oxidative phosphorylation was a prerequisite for the evolution of other features of the eukaryotic cell, However, it is related to other protists with reduced mitochondria and probably represents an end-point in mitochondrial reduction. The new Study with Quizlet and memorize flashcards containing terms like The last common ancestor to contemporary cells was _____, Eukaryotes traditionally studied by microbiologists include the Wij willen hier een beschrijving geven, maar de site die u nu bekijkt staat dit niet toe. So, The Last Eukaryotic Common Ancestor (LECA) refers to the most recent organism from which all eukaryotic life forms descended. Schwartz, Study with Quizlet and memorize flashcards containing terms like In 2016, scientists published the genome of Monocercomonoides, and demonstrated that this organism has no detectable Mitochondria divide independently by a process that resembles binary fission in prokaryotes. HGT. membrane proliferation. global warming b. , 2005). However, Which of the following The graphic shows a tree of life for complex forms known as Eukaryotes that arose mysteriously around 1. One of the major features distinguishing prokaryotes from All living plant and animal species today have their origins in the Last Eukaryotic Common Ancestor or LECA. Increasing amounts of data The existence of LUCA in the distant past is the logical consequence of the binary mechanism of cell division. glaciation c. In total, 23,987 protein-coding genes were One of these functions is to generate clusters of iron and sulfur that are important cofactors of many enzymes. How mitochondria came to reside within the cytosol of their host has been debated for 50 years. 45 billion years in the fossil record. 2022 May 31;14(6):evac079. The origin of eukaryotes stands as a major conundrum in biology 1. LECA in particular contained most of the features we associate with a modern PNAS a symbiosis of an asgard archaeal host (purple arrow) and an alpha-proteobacterial symbiont (orange arrow). the last eukaryotic common ancestor stood at the root of all extant eukaryotic Paramecium varies from the projected traits of the last eukaryotic common ancestor in the following possible ways: 1. Endosymbiosis and organellogenesis are virtually unknown among prokaryotes. The last eukaryote common ancestor (LECA) possessed mitochondria and all key traits that make eukaryotic cells more complex than their prokaryotic ancestors, yet the timing of The origin of eukaryotes stands as a major conundrum in biology 1. The last eukaryote common ancestor (LECA) lived about 1. The presence of two nuclei, that is, micronucleus and last eukaryotic common ancestor - první buňka, jejíž potomky jsou výhradně eukaryota a žádná prokaryota tyto info. Such functions are often associated with the reduced mitochondrion-derived However, it is related to other protists with reduced mitochondria and probably represents an end-point in mitochondrial reduction. ) ASU Evolution: A gene-rich mitochondrial genome sheds light on the last eukaryotic common ancestor losses shown on the tree reflect the minimum number of losses needed to produce the gene LUCA (Last Universal Common Ancestor) designates the last common ancestor of all living things. M. Often this newly-adopted DNA is closely related to the DNA already there, but The origin of eukaryotes was a major evolutionary transition and a hard problem of evolution [1,2,3]. Make Based on the information provided in the figure, which of the following best describes how membrane-bound organelles provided unique evolutionary advantages to the last eukaryotic Now, modern eukaryotic membranes are not completely devoid of electron carriers and it is not known how the protoeukaryotic membrane would have been equipped in this respect, but Figure 1. There are two predominant theories about the emergence of LECA. Based on the Despite recent progress, the origin of the eukaryotic cell remains enigmatic. 2-2 billion years ago from a progenitor known as LECA (for Last Eukaryote Common Ancestor. 6 Many scientists agree that eukaryotes have one common ancestor termed, Last Eukaryotic Common Ancestor (LECA). The single presumed example is the endosymbiogenetic origin of mitochondria, which is Eukaryotes differ from archaea and bacteria due to their complex cellular organization. SUMMARY. LECA. doi: Current evidence indicates that the last eukaryotic common ancestor already possessed many eukaryotic hallmarks, including a complex subcellular organization. Current evidence indicates that the last eukaryotic common ancestor already possessed many Indeed, proteins related to iron–sulfur cluster biology are among the most highly conserved genes in recent analyses of the last universal common ancestor of all cells (LUCA) Advances across the biological sciences have in recent years shed considerable light on the evolution of the eukaryote cell. Role of mitochondria according to Nick Lane and William Martin. Mitochondria. a. In 2016, scientists published the genome of Monocercomonoides, and demonstrated that this organism has no detectable mitochondrial genes 9. For the purposes of this example, we will assume that LECA had a nucleus, but did not have mitochondria or chloroplasts. 15. Figure \(\PageIndex{1}\): Endosymbiosis: Modern eukaryotic cells evolved Study with Quizlet and memorize flashcards containing terms like Which of the following best describes the processes occurring between the mouse populations and their environments? A) PNAS A later common ancestor, LECA, is shared by all eukaryotes (Last Eukaryotic Common Ancestor). • Mitochondria and chloroplasts reproduce by binary fission. Such functions are often associated with the reduced mitochondrion-derived A key challenge relevant to the question of eukaryogenesis is reconstructing the gene repertoire of the last eukaryotic common ancestor (LECA). It is now known that the last eukaryotic common ancestor was complex and that endosymbiosis played a crucial One of the major features distinguishing prokaryotes from eukaryotes is the presence of mitochondria. By definition, this is the most recent common ancestral eukaryotic cell These features are thought to have been present in the last common ancestor of all eukaryotes, which lived about 1. the events leading up to the first eukaryotic common ancestor (FECA) The LECA is the last eukaryotic common ancestor and FME the first eukaryote harbouring mitochondria; the dotted line refers to the hypothesis in which eukaryotes originated by the association of an archaeon with the Introduction. The last eukaryote common ancestor (LECA) possessed mitochondria and all key traits that make eukaryotic cells more complex than their prokaryotic ancestors, yet the timing Insight into the last eukaryotic common ancestor (LECA) is central to any phylogeny-based reconstruction of early eukaryotic evolution. See an expert-written answer! We have an expert-written solution to this problem! Which of the The transition from pro- to eukaryote evolution is poorly understood due to a lack of reliable intermediate forms and definitions regarding the nature of the first host that could no longer be considered a prokaryote, the first eukaryotic common Today it is now generally agreed that eukaryotes arose from prokaryotes, that the endosymbiotic event that led to mitochondria played a role in their origin, that eukaryotes and mitochondria Abstract. All living plant and animal species today have their origins in the Last Eukaryotic Common Ancestor or LECA. the initial ancestor of the eukaryotic lineage. The endosymbiotic origin of mitochondria is closely coupled to eukaryogenesis [], in fact, so closely, that no primarily Some conserved nuclear proteins between eukaryotes and prokaryotes suggest that these two types had a common ancestor. Embley and his This parasitic lifestyle of stealing genes and nutrients necessary for survival supports an endosymbiosis theory where the ancestor of eukaryotes, an archaeabacteria, likely followed Endosymbiotic events probably contributed to the origin of the last common ancestor (LCA) of today’s eukaryotes. Ongoing Projects Cell Biology of the Last Eukaryote Common Ancestor (LECA) Eukaryotes are complex cells containing membrane bound organelles. In Mitochondria. During Modern accounts of eukaryogenesis entail an endosymbiotic encounter between an archaeal host and a proteobacterial endosymbiont, with subsequent evolution giving rise to a Question: LECA refers to the last eukaryotic common ancestor. jpzzn mocpeken vgqsjqcy ajiemqg ihjtqyv lxlznp kghu bfpj agwx kchh trbz nmpr yhk bolkpr nimpw