I'm having trouble understanding the export function in rtracklayer. I have created an object of 3'-UTRs and can export them as gff. But I would like to also include the gene names in the gff-file. They are there in the column Name, but i don't know how to include this in the gff-file.

My script:

txdb = makeTxDbFromGFF(file = "transcripts.gtf", format = "gtf")
txdb

utr = threeUTRsByTranscript(txdb, use.names = TRUE)
asGFF(utr)
export(utr, "3_UTR.gff", format = "GFF")

I would like to also have the gene names under the column Name to appear in my gff-file:

> asGFF(utr)
GRanges object with 14983 ranges and 7 metadata columns:
                   seqnames         ranges strand |        type          ID
                      <Rle>      <IRanges>  <Rle> | <character> <character>
      [1]   Supercontig_1.1 [ 8533,  8777]      + |        mRNA       mRNA1
      [2]   Supercontig_1.1 [22263, 22394]      + |        mRNA       mRNA2
      [3]   Supercontig_1.1 [34734, 34943]      + |        mRNA       mRNA3
      [4]   Supercontig_1.1 [56043, 56381]      + |        mRNA       mRNA4
      [5]   Supercontig_1.1 [70457, 70507]      + |        mRNA       mRNA5
      ...               ...            ...    ... .         ...         ...
  [14979] Supercontig_1.994 [ 8764,  9020]      - |        exon    exon7593
  [14980] Supercontig_1.995 [23924, 24302]      + |        exon    exon7594
  [14981] Supercontig_1.995 [25442, 25477]      - |        exon    exon7595
  [14982] Supercontig_1.997 [18118, 19806]      - |        exon    exon7596
  [14983] Supercontig_1.998 [22519, 23126]      - |        exon    exon7597
                  Name   exon_id   exon_name exon_rank      Parent
           <character> <integer> <character> <integer> <character>
      [1] SARC_00001T0      <NA>        <NA>      <NA>        <NA>
      [2] SARC_00003T0      <NA>        <NA>      <NA>        <NA>
      [3] SARC_00004T0      <NA>        <NA>      <NA>        <NA>
      [4] SARC_00008T0      <NA>        <NA>      <NA>        <NA>
      [5] SARC_00011T0      <NA>        <NA>      <NA>        <NA>
      ...          ...       ...         ...       ...         ...
  [14979]         <NA>     65051        <NA>         6    mRNA7382
  [14980]         <NA>     65078        <NA>         5    mRNA7383
  [14981]         <NA>     65079        <NA>         1    mRNA7384
  [14982]         <NA>     65115        <NA>         4    mRNA7385
  [14983]         <NA>     65133        <NA>         5    mRNA7386
  -------
  seqinfo: 7751 sequences from an unspecified genome; no seqlengths

Output of my current gff-file:

##gff-version 1
##source-version rtracklayer 1.28.10
##date 2016-03-03
Supercontig_1.1    rtracklayer    mRNA    8533    8777    .    +    .    Supercontig_1.1
Supercontig_1.1    rtracklayer    mRNA    22263    22394    .    +    .    Supercontig_1.1
Supercontig_1.1    rtracklayer    mRNA    34734    34943    .    +    .    Supercontig_1.1
Supercontig_1.1    rtracklayer    mRNA    56043    56381    .    +    .    Supercontig_1.1
Supercontig_1.1    rtracklayer    mRNA    70457    70507    .    +    .    Supercontig_1.1
Supercontig_1.1    rtracklayer    mRNA    86426    87450    .    +    .    Supercontig_1.1

> sessionInfo()
R version 3.3.2 (2016-10-31)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: macOS Sierra 10.12.3

locale:
[1] C

attached base packages:
[1] stats4    parallel  stats     graphics  grDevices utils     datasets  methods  
[9] base     

other attached packages:
[1] rtracklayer_1.32.2     GenomicFeatures_1.24.5 AnnotationDbi_1.34.4  
[4] Biobase_2.32.0         GenomicRanges_1.24.3   GenomeInfoDb_1.8.7    
[7] IRanges_2.6.1          S4Vectors_0.10.3       BiocGenerics_0.18.0   

loaded via a namespace (and not attached):
 [1] Rcpp_0.12.8                XVector_0.12.1             zlibbioc_1.18.0           
 [4] GenomicAlignments_1.8.4    BiocParallel_1.6.6         tools_3.3.2               
 [7] SummarizedExperiment_1.2.3 DBI_0.5-1                  digest_0.6.10             
[10] bitops_1.0-6               RCurl_1.95-4.8             biomaRt_2.28.0            
[13] memoise_1.0.0              RSQLite_1.1                Biostrings_2.40.2         
[16] Rsamtools_1.24.0           XML_3.98-1.5      

You probably want to use version 3 of the format, by using the extension "gff3" or specifying format="3". Otherwise, it uses GFF version 1 by default, which is limited and so old that I can't even find the spec anymore.