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Previous issue date: 2014-03-24 / Genotyping of polymorphic short tandem repeats (STRs) loci is widely used in forensic DNA analysis. STR loci eventually present tri-allelic pattern as a genotyping irregularity and, in that situation, the doubt about the tri-allele locus calculation can reduce the analysis strength. Alleles at the TPOX STR locus have 6 14 different numbers of a four-nucleotide (AATG) repeat motif arranged in tandem. Although tri-allelic genotypes are generally rare, the TPOX tri-allelic pattern has a higher frequency, varying widely among populations. Despite this, there are few accurate reports to disclose the nature of the TPOX third allele. In this work we performed two studies: In the first one we present data obtained from 45 individuals belonging to the same pedigree, in which there were cases of tri-allelic TPOX genotypes. The subjects were apparently healthy with a normal biological development. We noticed six tri-allelic cases in this family, and all of them were women. Karyotype analysis showed no occurrence of partial 2p trisomy. All the tri-allelic cases had the genotype 8 10 11, probably due to three copies of the TPOX STR sequence in all cells (Type 2 tri-allelic pattern). Based on previous data we assumed an allele 10 as the TPOX third allele. The pedigree analyses show evidence that the TPOX extra allele was an allele 10, it is placed far from the main TPOX locus, and that there is a potential linkage of the TPOX extra-allele-10 with one marker on Xq. This was the first study that included a large pedigree analysis in order to understand the nature TPOX tri-allelic pattern. In the second study, we investigate whether there is a single third-extra allele in the TPOX tri-allelic pattern, what it is, and where it is. We looked for TPOX tri-allelic subjects in 75,113 Brazilian families. Considering only the parental generation (mother+father) we had 150,226 unrelated subjects evaluated. From this total, we found 88 unrelated subjects with tri-allelic pattern in the TPOX locus (0.06%; 88/150,226). Seventeen percent of these subjects (15/88) presented heterozygosis with peak imbalance, which we describe as a derived category to Clayton s Type 2 tri-allelic pattern (a higher peak of double dose homozygote plus a regular sized peak). In this paper we presented detailed data from 66 trios (mother+father+child; with true biological relationships) where the tri-allelic pattern was observed in the mother or in the father. In 39 of these families (39/66; 59%) the third-extra TPOX allele was transmitted either from the mother or from the father to the child. Our evidence indicated an allele 10 as the thirdextra TPOX allele, and it is on the X chromosome. The present data, which support the previous hypothesis, improve the knowledge about tri-allelic pattern of TPOX CODIS' locus allowing the use of TPOX profile in forensic analyses even when with tri-allelic pattern. This evaluation is now available for different forensic applications / A genotipagem de short tanden repeats ( STRs ) ? amplamente utilizada na an?lise de DNA forense, contudo eventuais ocorr?ncias de trialelias podem reduzir o poder da an?lise. Alelos do l?cus de STR TPOX tem de 6-14 n?meros diferentes do motivo de repeti??o em tandem de quatro nucleot?deos (AATG). Apesar dos gen?tipos tri-al?licos sejam geralmente raro, o padr?o tri-al?lico do TPOX tem uma alta freq??ncia, variando amplamente entre as popula??es. Apesar disso, h? poucos relatos precisos para divulgar a natureza do terceiro alelo do TPOX. Neste trabalho n?s realizamos dois estudos: No primeiro, apresentamos os dados obtidos a partir de 45 indiv?duos pertencentes ? mesma linhagem, em que houve casos de gen?tipos tri-al?licos do TPOX. Os indiv?duos foram aparentemente saud?vel, com um desenvolvimento biol?gico normal. Percebemos seis casos tri-al?licos nesta fam?lia, e todos eles foram em mulheres. A an?lise do cari?tipo mostrou nenhuma ocorr?ncia de trissomia parcial 2p. Todos os casos trial?licos tinham o gen?tipo 8-10-11, provavelmente devido a tr?s c?pias da seq??ncia do STR TPOX em todas as c?lulas (Padr?o tri-al?lico tipo 2). Com base nos dados anteriores, assumimos o alelo 10 como sendo o terceiro alelo do TPOX. As an?lises do pedigree mostraram evid?ncias de que o alelo extra do TPOX foi o alelo 10, ? localizado distante do l?cus principal do TPOX, e que existe um potencial de liga??o entre o alelo- extra-10 do TPOX com um marcador em Xq. Este foi o primeiro estudo que incluiu uma grande an?lise do pedigree, a fim de compreender a natureza do padr?o tri-al?lico do TPOX. No segundo estudo, investigamos se h? um ?nico terceiro extra-alelo no padr?o tri-al?lico do TPOX, o que ? ele, e onde est?. N?s pesquisamos por indiv?duos tri-al?licos no l?cus TPOX em 75.113 fam?lias brasileiras. Considerando apenas a gera??o parental (m?e + pai) tivemos 150.226 indiv?duos n?o relacionados avaliados. Desse total, encontramos 88 indiv?duos n?o relacionados com o padr?o tri-al?lico no l?cus TPOX (0,06%, 88/150, 226). Dezessete por cento destes indiv?duos (15/88) apresentaram heterozigoses com desbalan?o de picos, que descrevemos como uma categoria derivada do padr?o tri-al?lico de Clayton Tipo 2 (um pico mais alto de homozigoto dose dupla, mais um pico de tamanho regular). Neste trabalho, apresentamos dados detalhados de 66 trios (m?e + pai + filho; com verdadeiras rela??es biol?gicas) onde o padr?o tri-al?lico foi observado na m?e ou no pai. Em 39 destas fam?lias (39/66; 59%) o terceiro alelo-extra do TPOX foi transmitido tanto a partir da m?e ou do pai para a crian?a. Nossas evid?ncias indicaram o alelo 10 como sendo o terceiro alelo-extra do TPOX, e ele est? no cromossoma X. Os dados apresentados, os quais suportam as hip?teses anteriores, melhoram o entedimento sobre o padr?o tri-al?lico do l?cus TPOX do CODIS permitindo o uso do perfil TPOX em an?lises forense, mesmo quando com o padr?o tri-al?lico. Essa avalia??o est? agora dispon?vel para diferentes aplica??es forenses
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/5492 |
| Date | 24 March 2014 |
| Creators | Pican?o, Juliane Bentes |
| Contributors | Alho, Clarice Sampaio |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Biologia Celular e Molecular, PUCRS, BR, Faculdade de Bioci?ncias |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 8198246930096637360, 600, 600, 36528317262667714 |
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