Editing Alveolate (section)

==Characteristics==
The most notable shared characteristic is the presence of [[cortical alveolum|cortical (near the surface) alveoli (sacs)]]. These are flattened [[vesicle (biology)|vesicle]]s (sacs) arranged as a layer just under the [[cell membrane|membrane]] and supporting it, typically contributing to a flexible pellicle (thin skin). In armored [[dinoflagellates]] they may contain stiff plates. Alveolates have [[mitochondrion|mitochondria]] with tubular cristae ([[invaginations]]), and cells often have pore-like intrusions through the cell surface. The group contains free-living and [[parasitic]] organisms, predatory [[flagellates]], and [[photosynthetic]] organisms.

[[File:EM alveoli ciliate paramecium putrinum.jpg|600px|thumb|center|Transmission electron micrograph of a thin section of the surface of the ciliate ''[[Paramecium]] putrinum'', showing the alveoli (red arrows) under the cell surface]]

Almost all sequenced mitochondrial genomes of ciliates and apicomplexa are linear.<ref name="Barth2011">{{Cite journal |last1=Barth |first1=D |last2=Berendonk |first2=TU |year=2011 |title=The mitochondrial genome sequence of the ciliate ''Paramecium caudatum'' reveals a shift in nucleotide composition and codon usage within the genus ''Paramecium'' |journal=BMC Genomics |volume=12 |page=272 |doi=10.1186/1471-2164-12-272 |pmc=3118789 |pmid=21627782 |doi-access=free}}</ref> The mitochondria almost all carry [[mtDNA]] of their own but with greatly reduced genome sizes. Exceptions are ''[[Cryptosporidium]]'' which are left with only a [[mitosome]], the circular mitochondrial genomes of ''[[Acavomonas]]'' and ''[[Babesia microti]]'',<ref name="Obornik-Lukes-2015">{{Cite journal |last1=Oborník |first1=Miroslav |last2=Lukeš |first2=Julius |date=2015-10-15 |title=The Organellar Genomes of Chromera and Vitrella, the Phototrophic Relatives of Apicomplexan Parasites |url=https://www.annualreviews.org/content/journals/10.1146/annurev-micro-091014-104449 |journal=Annual Review of Microbiology |volume=69 |pages=129–144 |doi=10.1146/annurev-micro-091014-104449 |issn=0066-4227 |pmid=26092225 |access-date=2024-04-15}}</ref><ref name="Cornillot2012">{{Cite journal |vauthors=Cornillot E, Hadj-Kaddour K, Dassouli A, Noel B, Ranwez V, Vacherie B, Augagneur Y, Brès V, Duclos A, Randazzo S, Carcy B, Debierre-Grockiego F, Delbecq S, Moubri-Ménage K, Shams-Eldin H, Usmani-Brown S, Bringaud F, Wincker P, Vivarès CP, Schwarz RT, Schetters TP, Krause PJ, Gorenflot A, Berry V, Barbe V, Ben Mamoun C |year=2012 |title=Sequencing of the smallest Apicomplexan genome from the human pathogen ''Babesia microti'' |journal=Nucleic Acids Res. |volume=40 |issue=18 |pages=9102–14 |doi=10.1093/nar/gks700 |pmc=3467087 |pmid=22833609}}</ref> and ''[[Toxoplasma]]'''s highly fragmented mitochondrial genome, consisting of 21 sequence blocks which recombine to produce longer segments.<ref>{{Cite journal |last1=Namasivayam |first1=Sivaranjani |last2=Baptista |first2=Rodrigo P. |last3=Xiao |first3=Wenyuan |last4=Hall |first4=Erica M. |last5=Doggett |first5=Joseph S. |last6=Troell |first6=Karin |last7=Kissinger |first7=Jessica C. |date=May 2021 |title=A novel fragmented mitochondrial genome in the protist pathogen Toxoplasma gondii and related tissue coccidia |journal=Genome Research |volume=31 |issue=5 |pages=852–865 |doi=10.1101/gr.266403.120 |pmc=8092004 |pmid=33906963}}</ref><ref>{{Cite journal |last1=Namasivayam |first1=Sivaranjani |last2=Sun |first2=Cheng |last3=Bah |first3=Assiatu B. |last4=Oberstaller |first4=Jenna |last5=Pierre-Louis |first5=Edwin |last6=Etheridge |first6=Ronald Drew |last7=Feschotte |first7=Cedric |last8=Pritham |first8=Ellen J. |last9=Kissinger |first9=Jessica C. |date=2023-11-07 |title=Massive invasion of organellar DNA drives nuclear genome evolution in Toxoplasma |journal=Proceedings of the National Academy of Sciences |volume=120 |issue=45 |pages=–2308569120 |bibcode=2023PNAS..12008569N |doi=10.1073/pnas.2308569120 |pmc=10636329 |pmid=37917792 }}</ref>