Species-agnostic local ancestry inference with convolutions

Local Ancestry Inference (LAI) is the high resolution prediction of ancestry (African, European, ...) across a DNA sequence. LAI is becoming increasingly important in DNA sequence analysis for the study of human ancestry and migrations. It is also necessary for polygenic risk scores research (predic...

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Bibliographic Details
Author: Oriol Sàbat, Benet
Format: Master's thesis
Publication date:2021
Country:España
Institution:Universitat Politècnica de Catalunya (UPC)
Repository:UPCommons. Portal del coneixement obert de la UPC
Language:English
OAI Identifier:oai:upcommons.upc.edu:2117/360308
Online Access:https://hdl.handle.net/2117/360308
Access Level:Open access
Keyword:Genomics
Neural networks (Computer science)
genomics
convolution
ancestry
dna
local ancestry inference
neural
Genòmica
Xarxes neuronals (Informàtica)
Àrees temàtiques de la UPC::Enginyeria de la telecomunicació::Telemàtica i xarxes d'ordinadors
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author Oriol Sàbat, Benet
author_browse Oriol Sàbat, Benet
author_facet Oriol Sàbat, Benet
author_role author
collection UPCommons. Portal del coneixement obert de la UPC
description Local Ancestry Inference (LAI) is the high resolution prediction of ancestry (African, European, ...) across a DNA sequence. LAI is becoming increasingly important in DNA sequence analysis for the study of human ancestry and migrations. It is also necessary for polygenic risk scores research (prediction of traits and disease risk). Most current LAI models are built for specific species, set of ancestries and chromosomes, hence a new model needs to be trained from scratch for every slightly different setting. This creates a big barrier for research and industry to shift across different LAI scenarios. In this thesis we present SALAI-Net, the first statistical method for LAI with reference panel that can be used on any set of species and ancestries (species-agnostic). Loter is the state of the art in species-agnostic models with reference panel, and is based on a dynamic programming algorithm. However, it is slow and does not perform very well in small reference panel settings. Our model is based on a novel hand-engineered template matching block followed by a convolutional smoothing filter optimized to minimize cross-entropy loss on a training dataset. The right choice of DNA sequence encoding, similarity features and architecture is what makes our model able to generalize well to unseen ancestries, species, and different chromosomes. We benchmark our models on whole genome data of humans and we test the ability to generalize to dog species when trained on human data. Our models outperform the state-of-the-art method by a big margin in terms of accuracy, testing in different settings and datasets. Moreover, it is up to two orders of magnitude faster. Our model also shows close to no generalization gap when switching between species.
eu_rights_str_mv openAccess
format masterThesis
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institution Universitat Politècnica de Catalunya (UPC)
instname_str Universitat Politècnica de Catalunya (UPC)
language eng
network_acronym_str ES
network_name_str España
oai_identifier_str oai:upcommons.upc.edu:2117/360308
publishDate 2021
publishDateSort 2021
publisher Universitat Politècnica de Catalunya
publisherStr Universitat Politècnica de Catalunya
reponame_str UPCommons. Portal del coneixement obert de la UPC
spelling Species-agnostic local ancestry inference with convolutions Oriol Sàbat, Benet Genomics Neural networks (Computer science) genomics convolution ancestry dna local ancestry inference neural Genòmica Xarxes neuronals (Informàtica) Àrees temàtiques de la UPC::Enginyeria de la telecomunicació::Telemàtica i xarxes d'ordinadors Local Ancestry Inference (LAI) is the high resolution prediction of ancestry (African, European, ...) across a DNA sequence. LAI is becoming increasingly important in DNA sequence analysis for the study of human ancestry and migrations. It is also necessary for polygenic risk scores research (prediction of traits and disease risk). Most current LAI models are built for specific species, set of ancestries and chromosomes, hence a new model needs to be trained from scratch for every slightly different setting. This creates a big barrier for research and industry to shift across different LAI scenarios. In this thesis we present SALAI-Net, the first statistical method for LAI with reference panel that can be used on any set of species and ancestries (species-agnostic). Loter is the state of the art in species-agnostic models with reference panel, and is based on a dynamic programming algorithm. However, it is slow and does not perform very well in small reference panel settings. Our model is based on a novel hand-engineered template matching block followed by a convolutional smoothing filter optimized to minimize cross-entropy loss on a training dataset. The right choice of DNA sequence encoding, similarity features and architecture is what makes our model able to generalize well to unseen ancestries, species, and different chromosomes. We benchmark our models on whole genome data of humans and we test the ability to generalize to dog species when trained on human data. Our models outperform the state-of-the-art method by a big margin in terms of accuracy, testing in different settings and datasets. Moreover, it is up to two orders of magnitude faster. Our model also shows close to no generalization gap when switching between species. Universitat Politècnica de Catalunya https://hdl.handle.net/2117/360308
spellingShingle Species-agnostic local ancestry inference with convolutions
Oriol Sàbat, Benet
Genomics
Neural networks (Computer science)
genomics
convolution
ancestry
dna
local ancestry inference
neural
Genòmica
Xarxes neuronals (Informàtica)
Àrees temàtiques de la UPC::Enginyeria de la telecomunicació::Telemàtica i xarxes d'ordinadors
title Species-agnostic local ancestry inference with convolutions
title_full Species-agnostic local ancestry inference with convolutions
title_fullStr Species-agnostic local ancestry inference with convolutions
title_full_unstemmed Species-agnostic local ancestry inference with convolutions
title_short Species-agnostic local ancestry inference with convolutions
title_sort Species-agnostic local ancestry inference with convolutions
topic Genomics
Neural networks (Computer science)
genomics
convolution
ancestry
dna
local ancestry inference
neural
Genòmica
Xarxes neuronals (Informàtica)
Àrees temàtiques de la UPC::Enginyeria de la telecomunicació::Telemàtica i xarxes d'ordinadors
topic_facet Genomics
Neural networks (Computer science)
genomics
convolution
ancestry
dna
local ancestry inference
neural
Genòmica
Xarxes neuronals (Informàtica)
Àrees temàtiques de la UPC::Enginyeria de la telecomunicació::Telemàtica i xarxes d'ordinadors
url https://hdl.handle.net/2117/360308