Athena: Automated Tuning of k-mer based Genomic Error Correction Algorithms using Language Models
| Autor: | Mustafa Abdallah, Hany Ahmed, Ashraf Mahgoub, Somali Chaterji |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Perplexity Computer science 0206 medical engineering Oligonucleotides Datasets as Topic lcsh:Medicine 02 engineering and technology Article 03 medical and health sciences Automation Computational models Author Correction lcsh:Science Natural Language Processing Multidisciplinary Base Sequence lcsh:R High-Throughput Nucleotide Sequencing Genomics 030104 developmental biology Recurrent neural network k-mer lcsh:Q Language model Neural Networks Computer Error detection and correction Algorithm Sequence Alignment 020602 bioinformatics Algorithms |
| Zdroj: | Scientific Reports Scientific Reports, Vol 9, Iss 1, Pp 1-13 (2019) |
| ISSN: | 2045-2322 |
| Popis: | The performance of most error-correction (EC) algorithms that operate on genomics reads is dependent on the proper choice of its configuration parameters, such as the value of k in k-mer based techniques. In this work, we target the problem of finding the best values of these configuration parameters to optimize error correction and consequently improve genome assembly. We perform this in an adaptive manner, adapted to different datasets and to EC tools, due to the observation that different configuration parameters are optimal for different datasets, i.e., from different platforms and species, and vary with the EC algorithm being applied. We use language modeling techniques from the Natural Language Processing (NLP) domain in our algorithmic suite, Athena, to automatically tune the performance-sensitive configuration parameters. Through the use of N-Gram and Recurrent Neural Network (RNN) language modeling, we validate the intuition that the EC performance can be computed quantitatively and efficiently using the “perplexity” metric, repurposed from NLP. After training the language model, we show that the perplexity metric calculated from a sample of the test (or production) data has a strong negative correlation with the quality of error correction of erroneous NGS reads. Therefore, we use the perplexity metric to guide a hill climbing-based search, converging toward the best configuration parameter value. Our approach is suitable for both de novo and comparative sequencing (resequencing), eliminating the need for a reference genome to serve as the ground truth. We find that Athena can automatically find the optimal value of k with a very high accuracy for 7 real datasets and using 3 different k-mer based EC algorithms, Lighter, Blue, and Racer. The inverse relation between the perplexity metric and alignment rate exists under all our tested conditions—for real and synthetic datasets, for all kinds of sequencing errors (insertion, deletion, and substitution), and for high and low error rates. The absolute value of that correlation is at least 73%. In our experiments, the best value of k found by Athena achieves an alignment rate within 0.53% of the oracle best value of k found through brute force searching (i.e., scanning through the entire range of k values). Athena’s selected value of k lies within the top-3 best k values using N-Gram models and the top-5 best k values using RNN models With best parameter selection by Athena, the assembly quality (NG50) is improved by a Geometric Mean of 4.72X across the 7 real datasets. |
| Databáze: | OpenAIRE |
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