Coordinates of CDS sequence

Question

[hemr3]

Hi all,

I can't seem to get my head around the Genbank CDS coordinate numbers (see here: https://www.ncbi.nlm.nih.gov/nuccore/NC_000022.11?report=genbank&from=44881162&to=45010005&strand=true)

If I have a list of a CDS sequence here:

And the gene itself (both introns and exons) starts at place 0, would the coordinate of the first CDS be:

0+457 = 457

Or would this relate to the beginning of the first exon, which would start at place 100:

100+457 = 557

In image format:

Apologies if this is a stupid question!

[GenoMax]

Which specific gene are you referring to? There may be a 5'-UTR there.

[hemr3]

Hi! This is the CDS without any UTR in them (I believe), but I'm referring to PHF21B.

Answer 1

[Mensur Dlakic]

Counting starts from 1, not from 0. All the counts are from the very first nucleotide in that particular record, which is to say that they have the same frame of reference. That would be your option #1.