DOI: 10.5061/dryad.bcc2fqzsf
title: Reduced gene expression and missense mutations in the transporter protein SLC45A2 in a hypopigmented Egyptian rousette fruit bat (<em>Rousettus aegyptiacus</em>)

description: Oculocutaneous albinism—characterised by absent or decreased melanin in
 the skin, eyes, and hair—often co-occurs with sensory, skin, and immunity
 disorders. The genetic basis of albinism in humans is complex, with many
 loci implicated in multiple forms of the disorder. Less is known about the
 underlying genetic causes of albinism and leucism in other species, and
 cross-species studies of the molecular correlates of hypopigmentation
 could highlight common and conserved pathways underlying mammalian
 pigmentation disorders. We characterise the putative causal loci of
 reduced pigmentation in an Egyptian fruit bat (Rousettus aegyptiacus) that
 displayed features indicative of albinism. Despite albino or leucistic
 individuals having been reported in &gt;100 bat species, the
 associated genetic backgrounds have not previously been studied. We used a
 digital gene expression panel to quantify mRNA levels in wing membrane
 samples of four candidate pigmentation genes in the focal albino fruit bat
 and control individuals. Significantly reduced SLC45A2 mRNA expression was
 found in the albino compared to five bats with typical colouration.
 Additionally, intraspecific sequence analyses of the albino bat SLC45A2
 coding sequence identified two missense mutations, E18A and Q298R, the
 former of which was private to the albino bat. Position 18 of SLC45A2 was
 otherwise found to be highly conserved across 60 bat species and has not
 been previously linked to human albinism. By identifying SLC45A2 as the
 likely contributing locus, our results also indicate further support for
 the necessity of genetic testing for the reliable categorisation of
 hypopigmented animals as either albino or leucistic.
description: # Reduced gene expression and missense mutations in the transporter
 protein SLC45A2 in a hypopigmented Egyptian rousette fruit bat (*Rousettus
 aegyptiacus*) Dataset DOI:
 [10.5061/dryad.bcc2fqzsf](https://doi.org/10.5061/dryad.bcc2fqzsf) ##
 Description of the data and file structure This dataset contains data
 generated and used in analyses to test for the underlying genetic cause of
 hypopigmentation in an individual Egyptian rousette fruit bat (*Rousettus
 aegyptiacus*). The data includes gene expression values for four genes
 known to be associated with oculocutaneous albinism (OCA) in mammals, and
 sequence data for a single gene (the transporter protein SLC45A2)
 generated by Sanger sequencing from *R. aegyptiacus* bats. To place the
 sequence variants detected in the hypopigmented bat in a wider
 evolutionary context, *SLC45A2* coding sequences were also extracted from
 genomes and transcriptomes in 60 bat species and compared. ### Files and
 variables #### File: SLC45A2_SangerBats.zip **Description:** This zipped
 folder contains the raw Sanger sequencing files (.ab1, .scf, and .seq)
 produced for two *R. aegyptiacus* bats (CPN010 – hypopigmented and CPN006
 – typical colouration). All seven exons of the SLC45A2 gene were sequenced
 as identified by E1–E7 in the file names. Sanger sequencing was performed
 in both directions: forward (FOR) and reverse (REV).  #### File:
 SLC45A2_BAT_transcriptomes.fas **Description:** SLC45A2 coding sequence
 nucleotide alignment generated for 60 bat species and *Homo sapiens*.
 Sequences were extracted from genomes, transcriptomes and obtained from
 Sanger sequencing. Sequences were aligned with Clustal X and manually
 edited where necessary, (‘?’ – missing data, ‘-’ – alignment gap). See
 Table S5 of the accompanying paper for data source information.  ####
 File: SLC45A2_BAT_isoforms.fasta **Description:** SLC45A2 coding sequence
 nucleotide alignment of the two alternative isoforms retrieved from
 transcriptomes from across multiple individuals of *Artibeus jamaicensis,
 Phyllops falcatus, and Pteronotus parnellii pusillus*, (‘?’ – missing
 data, ‘-’ – alignment gap)*.* #### File: Rousettus_nCounter_raw.csv
 **Description:** Raw nCounter gene expression values for four genes
 associated with oculocutaneous albinism (OCA) in mammals (TYR, OCA2,
 TYRP1, and SLC45A2) and three housekeeping genes (ABCF1, EIF2B4, and
 GUSB). Values for eight negative (A–H) and six positive (A–F) controls are
 also provided. Expression values were measured across six bats (CPN003,
 CPN004, CPN005, CPN006, CPN008 and CPN010) from tissue sampled at four
 points from the wing (WL1 – leading 1, WL2 – leading 2, WM3 – mid-wing 3,
 and WT4 – wing tip 4) and one sample of skin from the arm (SA). Note: in
 the above table NA refers to ‘not applicable’, as positive and negative
 controls do not have corresponding gene accession numbers. ##### Variables
 * Probe_Name: This is the name of each probe for which expression data was
 collected. Names consist of the gene under study (TYR, OCA2, TYRP1,
 SLC45A2, ABCF1, EIF2B4, and GUSB), and the dataset (Rousettus). Negative
 controls begin with ‘NEG_’ and positive controls ‘POS_’. * Accession#:
 This variable provides the *Rousettus aegyptiacus* genomic sequence
 accession number that was used to design probes for the seven genes
 included in the study. * Class_Name: Designates whether the probe
 corresponds to either an ‘Endogenous’ gene, a ‘Housekeeping’ gene, a
 ‘Negative’ or a ‘Positive’ control.