A potential role for epigenetic mechanisms enabling appropriate seasonal reproductive transitions of liver yolk-precursor production

Animals utilize mechanisms that enable breeding at times that ensure offspring production and growth during periods of abundant resources. DNA methylation is one mechanism by which the expression of genes necessary for reproduction may be regulated so that they are expressed only at appropriate times of the year. To date, much work on seasonal breeding in vertebrates has focused on the neuroendocrine system; however, oviparous vertebrates, including birds, must also rely on the liver for the production of yolk precursor hormones that will provide the nutrients necessary for developing young in ovo. We hypothesized that changes in DNA methylation in the liver may be one mechanism ensuring appropriately timed seasonal breeding. We observed that liver expression of (VTG2) was upregulated in birds sampled during the early breeding compared with those sampled during the pre-breeding period, and also observed changes in liver expression of DNMT1 and DNMT3a between these two periods. Cont..., , , # A potential role for epigenetic mechanisms enabling appropriate seasonal reproductive transitions of liver yolk-precursor production

Dataset DOI: [10.5061/dryad.9zw3r22rw](10.5061/dryad.9zw3r22rw)

## Description of the data and file structure

Each individual was sacrificed during one of two sampling periods as described in the text. All individuals had their DNA bisulfite converted and the percent of methylation at the targeted sites denoted in the text were analyzed using pyrosequencing.  Pyrosequencing results that did not meet quality control criteria described in the text were not included in the analysis.

### Files and variables

#### File: methylation.junco.combined.DRYAD.withage.csv

**Description:** 

##### Variables

* Female No.: Female number was assigned to each bird captured and sampled sequentially. Cells marked 'null' had no age information recorded on the datasheet. 
* age: AY are birds determined as young adults (after hatch year) in their first breeding year usin...,