Fandom

VroniPlag Wiki

Analyse:Eka/Fragment 019 01

31.268Seiten in
diesem Wiki
Seite hinzufügen
Diskussion0

Störung durch Adblocker erkannt!


Wikia ist eine gebührenfreie Seite, die sich durch Werbung finanziert. Benutzer, die Adblocker einsetzen, haben eine modifizierte Ansicht der Seite.

Wikia ist nicht verfügbar, wenn du weitere Modifikationen in dem Adblocker-Programm gemacht hast. Wenn du sie entfernst, dann wird die Seite ohne Probleme geladen.


Typus
BauernOpfer
Bearbeiter
SleepyHollow02
Gesichtet
No.png
Untersuchte Arbeit:
Seite: 19, Zeilen: 1 ff.
Quelle: Edelmann Hirschhorn 2009
Seite(n): 158 f., Zeilen: 158: right col: 13 ff.; 159: left col. 1 ff.
[The current limitations of the technology include the inability to detect] balanced chromosome rearrangements and the equivocal nature of copy number alterations of unknown significance that may be identified. Nevertheless, it is being used routinely in the clinical setting with a normal chromosome result in cases of mental retardation and/or multiple congenital anomalies (MR/MCA); as a result the diagnostic yield in this patient group has increased considerably.

3 1.2 Array – CGH Methodologies

Two major types of array targets are currently being utilized. Initially, bacterial artificial chromosomes (BACs) were the array target of choice.6 However, more recently, oligonucleotide arrays have been adopted due to the increased genome coverage they afford. The design of both array types was made possible by the availability of the complete map and sequence of the human genome. The BAC arrays may contain DNA isolated from large insert clones that range in size from 150–200 kb, spotted directly onto the array or may employ the spotting of PCR products amplified from the BAC clones.8 These arrays are generally very sensitive and results can be directly validated with FISH using the BAC DNA as a probe. However, production of BAC DNA is labor-intensive, and the resolution is limited to 50–100 kb, even on a whole genome tiling path array.9 Oligonucleotide arrays offer a flexible format with the potential for very high resolution and customization. Several different platforms are available for oligonucleotide arrays, some of which were adapted from genomewide SNP-based oligonucleotide markers and others that were created from a library of virtual probes that span the genome, and consequently can be constructed to have extremely high resolution.10 Both BAC and oligonucleotide arrays have been used successfully to detect copy number changes in patients with MR/MCA and autism. A number of different array design approaches have been taken for diagnostic purposes. A targeted array is one that contains specific regions of the genome, such as the subtelomeres and those responsible for known microdeletion/microduplication syndromes, but does not have probes that span the whole genome.11-13 This type of [array was initially used for clinical applications in postnatal specimens but has also been implemented for prenatal specimens with an abnormal ultrasound finding or for general screening purposes.14-16]


6 Pinkel D, Segraves R, Sudar D et al: High resolution analysis of DNA copy number variation using comparative genomic hybridization to microarrays. Nat Genet 1998; 20: 207-211.

7 Cai WW, Mao JH, Chow CW, Damani S, Balmain A, Bradley A: Genome-wide detection of chromosomal imbalances in tumors using BAC microarrays. Nat Biotechnol 2002; 20: 393-396.

8 Ylstra B, van den Ijssel P, Carvalho B, Brakenhoff RH, Meijer GA: BAC to the future! or oligonucleotides: a perspective for micro array comparative genomic hybridization (array CGH). Nucleic Acids Res 2006; 34: 445-450.

9 Ishkanian AS, Malloff CA, Watson SK et al: A tiling resolution DNA microarray with complete coverage of the human genome. Nat Genet 2004; 36: 299-303.

10 Shaikh TH: Oligonucleotide arrays for high-resolution analysis of copy number alteration in mental retardation/multiple congenital anomalies. Genet Med 2007; 9: 617-625.

11 Bejjani BA, Saleki R, Ballif BC et al: Use of targeted array-based CGH for the clinical diagnosis of chromosomal imbalance: is less more? Am J Med Genet A 2005; 134: 259-267.

12 Bejjani BA, Shaffer LG: Application of array-based comparative genomic hybridization to clinical diagnostics. J Mol Diagn 2006; 8: 528-533.

13 Shaffer LG, Kashork CD, Saleki R et al: Targeted genomic microarray analysis for identification of chromosome abnormalities in 1500 consecutive clinical cases. J Pediatr 2006; 149: 98-102.

14 Le Caignec C, Boceno M, Saugier-Veber P et al: Detection of genomic imbalances by array based comparative genomic hybridisation in fetuses with multiple malformations. J Med Genet 2005; 42: 121-128.

15 Sahoo T, Cheung SW, Ward P et al: Prenatal diagnosis of chromosomal abnormalities using array-based comparative genomic hybridization. Genet Med 2006; 8: 719-727.

16 Kitsiou-Tzeli S, Sismani C, Karkaletsi M et al: Prenatal diagnosis of a de novo partial trisomy 10p12.1-12.2 pter originating from an unbalanced translocation onto 15qter and confirmed with array CGH. Prenat Diagn 2008; 28: 770-772.

The current limitations of the technology include the inability to detect balanced chromosome rearrangements and the equivocal nature of copy number alterations of unknown significance that may be identified. Nevertheless, it is being used routinely in the clinical setting with a normal chromosome result in cases of mental retardation and/or multiple congenital anomalies (MR/MCA); as a result the diagnostic yield in this patient group has increased considerably.

Array CGH Methodologies

Two major types of array targets are currently being utilized. Initially, bacterial artificial chromosomes (BACs) were the array target of choice.12 However, more recently, oligonucleotide arrays have been adopted due to the increased genome coverage they afford. The design of both array types was made possible by the availability of the complete map and sequence of the human genome. The BAC arrays may contain DNA isolated from large insert clones that range in size from 150–200 kb, spotted directly onto the array or may employ the spotting of PCR products amplified from the BAC clones.14 These arrays are generally very sensitive and results can be directly validated with FISH using the BAC DNA as a probe. However, production of BAC DNA is labor-intensive, and the resolution is limited to 50–100 kb, even on a whole genome tiling path

[page 159:]

array.15 Oligonucleotide arrays offer a flexible format with the potential for very high resolution and customization. Several different platforms are available for oligonucleotide arrays that range from 25- to 85mers in length, some of which were adapted from genomewide SNP-based oligonucleotide markers and others that were created from a library of virtual probes that span the genome, and consequently can be constructed to have extremely high resolution. 16 Both BAC and oligonucleotide arrays have been used successfully to detect copy number changes in patients with MR/MCA and autism. A number of different array design approaches have been taken for diagnostic purposes. A targeted array is one that contains specific regions of the genome, such as the subtelomeres and those responsible for known microdeletion/ microduplication syndromes, but does not have probes that span the whole genome.17–19 This type of array was initially used for clinical applications in postnatal specimens but has also been implemented for prenatal specimens with an abnormal ultrasound finding or for general screening purposes.20,21


12. Pinkel,D. et al. 1998. High resolution analysis ofDNA copy number variation using comparative genomic hybridization to microarrays. Nat. Genet. 20: 207–211.

13. Cai, W.W. et al. 2002. Genome-wide detection of chromosomal imbalances in tumors using BAC microarrays. Nat. Biotechnol. 20: 393–396.

14. Ylstra, B. et al. 2006. BAC to the future! Or oligonucleotides: A perspective for micro array comparative genomic hybridization (array CGH). Nucleic Acids Res. 34: 445–450.

15. Ishkanian, A.S. et al. 2004. A tiling resolution DNA microarray with complete coverage of the human genome. Nat. Genet. 36: 299–303.

16. Shaikh, T.H. 2007. Oligonucleotide arrays for highresolution analysis of copy number alteration in mental retardation/multiple congenital anomalies. Genet. Med. 9: 617–625.

17. Bejjani, B.A. et al. 2005. Use of targeted array-based CGH for the clinical diagnosis of chromosomal imbalance: Is less more? Am. J. Med. Genet. A 134: 259– 267.

18. Bejjani, B.A. & L.G. Shaffer. 2006. Application of array-based comparative genomic hybridization to clinical diagnostics. J. Mol. Diagn. 8: 528–533.

19. Shaffer, L.G. et al. 2006. Targeted genomic microarray analysis for identification of chromosome abnormalities in 1500 consecutive clinical cases. J. Pediatr. 149: 98–102.

20. Le Caignec, C. et al. (2005. Detection of genomic imbalances by array based comparative genomic hybridisation in fetuses with multiple malformations. J. Med. Genet. 42: 121–128.

21. Sahoo, T. et al. 2006. Prenatal diagnosis of chromosomal abnormalities using array-based comparative genomic hybridization. Genet. Med. 8: 719–727.

Anmerkungen
Sichter
(SleepyHollow02)

Auch bei Fandom

Zufälliges Wiki