Local Blast Question About The Genome Download

Hello All,

I have trying to go local blast for my genes (55 in number). I need to find the genes in all the mammalia class. I was trying to download the genomes for all the species of interest but I could not.

I need the nucleotide sequences for blastn program. I looked up every possible dataset but nothing worked.

It will be a great relief if someone can suggest a way. I also tried with blast preformatted datasets. So, I was trying to download the genomes for the species but the fasta sequences are available for the chromosomes.(as full chromosome sequence and not genes).

Thanks.