Paper · 2020 · Frontiers in Plant Science

Exploring Deep Learning for Complex Trait Genomic Prediction in Polyploid Outcrossing Species

Laura M. Zingaretti; Salvador Alejandro Gezan; Luis Felipe V. Ferrão; et al.

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verbatim quotes
182
citations
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research areas
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Open access · cc-by

Abstract

Genomic prediction (GP) is the procedure whereby the genetic merits of untested candidates are predicted using genome wide marker information. Although numerous examples of GP exist in plants and animals, applications to polyploid organisms are still scarce, partly due to limited genome resources and the complexity of this system. Deep learning (DL) techniques comprise a heterogeneous collection of machine learning algorithms that have excelled at many prediction tasks. A potential advantage of DL for GP over standard linear model methods is that DL can potentially take into account all genetic interactions, including dominance and epistasis, which are expected to be of special relevance in most polyploids. In this study, we evaluated the predictive accuracy of linear and DL techniques in two important small fruits or berries: strawberry and blueberry. The two datasets contained a total of 1,358 allopolyploid strawberry (2n=8x=112) and 1,802 autopolyploid blueberry (2n=4x=48) individuals, genotyped for 9,908 and 73,045 single nucleotide polymorphism (SNP) markers, respectively, and phenotyped for five agronomic traits each. DL depends on numerous parameters that influence performance and optimizing hyperparameter values can be a critical step. Here we show that interactions between hyperparameter combinations should be expected and that the number of convolutional filters and regularization in the first layers can have an important effect on model performance. In terms of genomic prediction, we did not find an advantage of DL over linear model methods, except when the epistasis component was important. Linear Bayesian models were better than convolutional neural networks for the full additive architecture, whereas the opposite was observed under strong epistasis. However, by using a parameterization capable of taking into account these non-linear effects, Bayesian linear models can match or exceed the predictive accuracy of DL. A semiautomatic implementation of the DL pipeline is available at https://github.com/lauzingaretti/deepGP/.

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Claims 5

Method / resourceobservedoriginal resultno effectmeasured

Claim · model-written summary

Deep learning showed no advantage over linear model methods for genomic prediction, except when epistasis was important.

Taxon
strawberry and blueberrye0
Outcome
genomic predictione1
Comparator
linear model methodse1

Verbatim

e0

“two important small fruits or berries: strawberry and blueberry”

✓ located verbatim in the source · abstract, characters 800–863 · show in text ↑
e1

“In terms of genomic prediction, we did not find an advantage of DL over linear model methods, except when the epistasis component was important”

✓ located verbatim in the source · abstract, characters 1485–1628 · show in text ↑
Method / resourceobservedoriginal resultpositivemeasured

Claim · model-written summary

For the full additive architecture, linear Bayesian models were better than convolutional neural networks in predictive accuracy.

Taxon
strawberry and blueberrye0
Outcome
predictive accuracye3
Direction
bettere2
Qualifier
full additive architecturee2
Comparator
convolutional neural networkse2

Verbatim

e0

“two important small fruits or berries: strawberry and blueberry”

✓ located verbatim in the source · abstract, characters 800–863 · show in text ↑
e2

“Linear Bayesian models were better than convolutional neural networks for the full additive architecture, whereas the opposite was observed under strong epistasis”

✓ located verbatim in the source · abstract, characters 1630–1792 · show in text ↑
e3

“Bayesian linear models can match or exceed the predictive accuracy of DL”

✓ located verbatim in the source · abstract, characters 1888–1960 · show in text ↑
Method / resourceobservedoriginal resultpositivemeasured

Claim · model-written summary

Under strong epistasis, convolutional neural networks outperformed linear Bayesian models in predictive accuracy.

Taxon
strawberry and blueberrye0
Outcome
predictive accuracye3
Qualifier
strong epistasise2
Comparator
Linear Bayesian modelse2

Verbatim

e0

“two important small fruits or berries: strawberry and blueberry”

✓ located verbatim in the source · abstract, characters 800–863 · show in text ↑
e2

“Linear Bayesian models were better than convolutional neural networks for the full additive architecture, whereas the opposite was observed under strong epistasis”

✓ located verbatim in the source · abstract, characters 1630–1792 · show in text ↑
e3

“Bayesian linear models can match or exceed the predictive accuracy of DL”

✓ located verbatim in the source · abstract, characters 1888–1960 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

The number of convolutional filters and regularization in the first layers can have an important effect on deep learning model performance.

Taxon
strawberry and blueberrye0
Outcome
model performancee4
Qualifier
number of convolutional filters and regularization in the first layerse4

Verbatim

e0

“two important small fruits or berries: strawberry and blueberry”

✓ located verbatim in the source · abstract, characters 800–863 · show in text ↑
e4

“the number of convolutional filters and regularization in the first layers can have an important effect on model performance”

✓ located verbatim in the source · abstract, characters 1359–1483 · show in text ↑
Method / resourceobservedoriginal resultpositivemeasured

Claim · model-written summary

With a parameterization for non-linear effects, Bayesian linear models can match or exceed the predictive accuracy of deep learning.

Taxon
strawberry and blueberrye0
Outcome
predictive accuracye3
Comparator
DLe3

Verbatim

e0

“two important small fruits or berries: strawberry and blueberry”

✓ located verbatim in the source · abstract, characters 800–863 · show in text ↑
e3

“Bayesian linear models can match or exceed the predictive accuracy of DL”

✓ located verbatim in the source · abstract, characters 1888–1960 · show in text ↑