Exploring DNA Methylation Diversity in the Honey Bee Brain by Ultra-Deep Amplicon Sequencing

Understanding methylation dynamics in organs or tissues containing many different cell types is a challenging task that cannot be efficiently addressed by the low-depth bisulphite sequencing of DNA extracted from such sources. Here we explored the feasibility of ultra-deep bisulphite sequencing of l...

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Main Authors: Robert Kucharski, Ryszard Maleszka
Format: Article
Language:English
Published: MDPI AG 2020-06-01
Series:Epigenomes
Subjects:
Online Access:https://www.mdpi.com/2075-4655/4/2/10
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author Robert Kucharski
Ryszard Maleszka
author_facet Robert Kucharski
Ryszard Maleszka
author_sort Robert Kucharski
collection DOAJ
description Understanding methylation dynamics in organs or tissues containing many different cell types is a challenging task that cannot be efficiently addressed by the low-depth bisulphite sequencing of DNA extracted from such sources. Here we explored the feasibility of ultra-deep bisulphite sequencing of long amplicons to reveal the brain methylation patterns in three selected honey bee genes analysed across five distinct conditions on the Illumina MiSeq platform. By combing 15 libraries in one run we achieved a very high sequencing depth of 240,000–340,000 reads per amplicon, suggesting that most of the cell types in the honey bee brain, containing approximately 1 million neurons, are represented in this dataset. We found a small number of gene-specific patterns for each condition in individuals of different ages and performing distinct tasks with 80–90% of those were represented by no more than a dozen patterns. One possibility is that such a small number of frequent patterns is the result of differentially methylated epialleles, whereas the rare and less frequent patterns reflect activity-dependent modifications. The condition-specific methylation differences within each gene appear to be position-dependent with some CpGs showing significant changes and others remaining stable in a methylated or non-methylated state. Interestingly, no significant loss of methylation was detected in very old individuals. Our findings imply that these diverse patterns represent a special challenge in the analyses of DNA methylation in complex tissues and organs that cannot be investigated by low-depth genome-wide bisulphite sequencing. We conclude that ultra-deep sequencing of gene-specific amplicons combined with genotyping of differentially methylated epialleles is an effective way to facilitate more advanced neuro-epigenomic studies in honey bees and other insects.
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spelling doaj.art-9479a74c740b46f8a25d0d7c3a494e322023-11-20T04:58:37ZengMDPI AGEpigenomes2075-46552020-06-01421010.3390/epigenomes4020010Exploring DNA Methylation Diversity in the Honey Bee Brain by Ultra-Deep Amplicon SequencingRobert Kucharski0Ryszard Maleszka1Research School of Biology, Australian National University, Canberra, ACT 2601, AustraliaResearch School of Biology, Australian National University, Canberra, ACT 2601, AustraliaUnderstanding methylation dynamics in organs or tissues containing many different cell types is a challenging task that cannot be efficiently addressed by the low-depth bisulphite sequencing of DNA extracted from such sources. Here we explored the feasibility of ultra-deep bisulphite sequencing of long amplicons to reveal the brain methylation patterns in three selected honey bee genes analysed across five distinct conditions on the Illumina MiSeq platform. By combing 15 libraries in one run we achieved a very high sequencing depth of 240,000–340,000 reads per amplicon, suggesting that most of the cell types in the honey bee brain, containing approximately 1 million neurons, are represented in this dataset. We found a small number of gene-specific patterns for each condition in individuals of different ages and performing distinct tasks with 80–90% of those were represented by no more than a dozen patterns. One possibility is that such a small number of frequent patterns is the result of differentially methylated epialleles, whereas the rare and less frequent patterns reflect activity-dependent modifications. The condition-specific methylation differences within each gene appear to be position-dependent with some CpGs showing significant changes and others remaining stable in a methylated or non-methylated state. Interestingly, no significant loss of methylation was detected in very old individuals. Our findings imply that these diverse patterns represent a special challenge in the analyses of DNA methylation in complex tissues and organs that cannot be investigated by low-depth genome-wide bisulphite sequencing. We conclude that ultra-deep sequencing of gene-specific amplicons combined with genotyping of differentially methylated epialleles is an effective way to facilitate more advanced neuro-epigenomic studies in honey bees and other insects.https://www.mdpi.com/2075-4655/4/2/10DNA methylationepiallelesbrain epigenomecellular diversitysocial insectgene expression
spellingShingle Robert Kucharski
Ryszard Maleszka
Exploring DNA Methylation Diversity in the Honey Bee Brain by Ultra-Deep Amplicon Sequencing
Epigenomes
DNA methylation
epialleles
brain epigenome
cellular diversity
social insect
gene expression
title Exploring DNA Methylation Diversity in the Honey Bee Brain by Ultra-Deep Amplicon Sequencing
title_full Exploring DNA Methylation Diversity in the Honey Bee Brain by Ultra-Deep Amplicon Sequencing
title_fullStr Exploring DNA Methylation Diversity in the Honey Bee Brain by Ultra-Deep Amplicon Sequencing
title_full_unstemmed Exploring DNA Methylation Diversity in the Honey Bee Brain by Ultra-Deep Amplicon Sequencing
title_short Exploring DNA Methylation Diversity in the Honey Bee Brain by Ultra-Deep Amplicon Sequencing
title_sort exploring dna methylation diversity in the honey bee brain by ultra deep amplicon sequencing
topic DNA methylation
epialleles
brain epigenome
cellular diversity
social insect
gene expression
url https://www.mdpi.com/2075-4655/4/2/10
work_keys_str_mv AT robertkucharski exploringdnamethylationdiversityinthehoneybeebrainbyultradeepampliconsequencing
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