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No dia 27 de abril de 2023, Thayn\u00e1 Juliane Guerra da Silva aluna de Mestrado do Programa de P\u00f3s-gradua\u00e7\u00e3o em Biodiversidade Vegetal e Meio Ambiente do Instituto de Pesquisas Ambientais defendeu sua disserta\u00e7\u00e3o intitulada \u201c Papel das varia\u00e7\u00f5es nas fam\u00edlias de dna repetitivo em brasiliorchis <\/em>r.b.singer, s.koehler & carnevali (orchidaceae)\u201d, de forma remota atrav\u00e9s da plataforma google meet.<\/p>\n A banca examinadora foi presidida pela sua orientadora Profa. Dra. Ana Paula de Moraes Universidade Federal do ABC (UFABC), tendo como membros Dra Magdalena Vaio Universidad de la Rep\u00fablica UdelaR (UDELAR)) e Dra. G\u00e9ssica Souza Ramos Universidade do Estado da Bahia (UNEB).<\/p>\n The species Brasiliorchis schunkeana<\/em>, a species of typical black flowers, stands out also for presenting large blocks of AT-rich heterochromatin in six of its 40 chromosomes. The presence of heterochromatic blocks is a common characteristic, but these are commonly formed by CG-rich DNAsat that form bands on the chromosomes. AT-rich heterochromatic blocks that occupy almost all of the chromosomes are rare. In association with these large blocks, this species presents an increase in GS (2C=4.19pg) compared to other species in the genus (average 2C=3.19pg), but with maintenance of the chromosome number (2n=40 in all species of the genus). Changes in GS in plants are often attributed to the expansion\/retraction of TEs, dispersed repetitive sequences. Thus, this dissertation aimed to identify whether the variation in GS in B. schunkeana <\/em>is due to variation in the fraction of TEs or DNAsat and which sequence(s) caused the change in GS. To perform this study, a comparative genomic analysis was carried out between B. schunkeana <\/em>and the type species of the genus, B. picta<\/em>. The main component of the repeatome of both species is constituted by LTR retroelements, with the OGRE lineage being the most representative. However, the TE composition is homogeneous between the two species, unlike the fraction of DNAsat: 6% of the genome (9% of the repeatome) of B. schunkeana <\/em>was annotated as DNAsat, twice the amount annotated for B. picta<\/em>. Of the three most representative DNAsat clusters, two have an AT-rich composition, which is compatible with the presence of DAPI+ heterochromatic blocks in the genome of B. schunkeana<\/em>. Finally, we conclude that the variation in genome size in B. schunkeana <\/em>is due to the amplification of DNAsat, CL 32 and 51 sequences, and not to the expansion of TEs.<\/p>\n Keyword<\/strong>: Satellite DNA, Transposable Elements, NGS.<\/p>\n A esp\u00e9cie Brasiliorchis schunkeana<\/em>, uma esp\u00e9cie de flores negras t\u00edpicas, se destaca tamb\u00e9m por apresentar grandes blocos de heterocromatina ricos em AT em seis dos seus 40 cromossomos. A presen\u00e7a de blocos heterocrom\u00e1ticos \u00e9 uma caracter\u00edstica comum, por\u00e9m estes s\u00e3o comumente formados por DNAsat rico em CG que formam faixas nos cromossomos. Blocos heterocrom\u00e1ticos ricos em AT e que ocupam quase a totalidade dos cromossomos s\u00e3o raros. Em associa\u00e7\u00e3o a esses grandes blocos, essa esp\u00e9cie apresenta um aumento do GS (2C=4,19pg) em compara\u00e7\u00e3o com as demais esp\u00e9cies do g\u00eanero (2C m\u00e9dio=3,19pg), mas com manuten\u00e7\u00e3o do n\u00famero cromoss\u00f4mico (2n=40 em todas as esp\u00e9cies do g\u00eanero). Altera\u00e7\u00f5es no GS em plantas s\u00e3o frequentemente atribu\u00eddas \u00e0 expans\u00e3o\/retra\u00e7\u00e3o de TEs, sequ\u00eancias repetitivas dispersas. Dessa forma, esta disserta\u00e7\u00e3o visou identificar se a varia\u00e7\u00e3o do GS em B. schunkeana <\/em>deve-se \u00e0 varia\u00e7\u00e3o na fra\u00e7\u00e3o de TEs ou DNAsat e qual(is) sequ\u00eancia(s) causaram a mudan\u00e7a no GS. Para realizar tal estudo, foi feita uma an\u00e1lise gen\u00f4mica comparativa entre B. schunkeana <\/em>e a esp\u00e9cie tipo do g\u00eanero, B. picta<\/em>. O principal componente do repetoma das duas esp\u00e9cies \u00e9 constitu\u00eddo por retroelementos do tipo LTR, com a linhagem OGRE sendo a mais representativa. Por\u00e9m a composi\u00e7\u00e3o de TE \u00e9 homog\u00eanea entre as duas esp\u00e9cies, diferente da fra\u00e7\u00e3o de DNAsat: 6% do genoma (9% do repetoma) de B. schunkeana <\/em>foi anotado como DNAsat, <\/em>o dobro do anotado para B. picta. <\/em>Dos tr\u00eas cluster mais representativos de DNAsat, dois apresentam composi\u00e7\u00e3o rica em AT, o que \u00e9 compat\u00edvel com a presen\u00e7a de blocos heterocrom\u00e1ticos DAPI+ no genoma de B. schunkeana<\/em>. Por fim, concluimos que a varia\u00e7\u00e3o do tamanho de genoma em B. schunkeana <\/em>deve-se a amplifica\u00e7\u00e3o de DNAsat, sequ\u00eancias CL 32 e 51, e n\u00e3o a expans\u00e3o de TE.<\/p>\n Palavra-chave:<\/strong> DNA sat\u00e9lite, Elemento transpon\u00edveis, NGS.<\/p>\n
\nPapel das varia\u00e7\u00f5es nas fam\u00edlias de DNA repetitivo em brasiliorchis<\/em> singer, koehler & carnevali (orchidaceae)<\/h3>\n
\nABSTRACT<\/strong><\/h4>\n
RESUMO<\/strong><\/h4>\n
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<\/a>Thayn\u00e1 Juliane Guerra da Silva<\/strong><\/a>
\nPapel das varia\u00e7\u00f5es nas fam\u00edlias de DNA repetitivo em brasiliorchis<\/em> singer, koehler & carnevali (orchidaceae)<\/a><\/p>\n
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