suppose this fern gametophyte was all alone. in other words, it was completely isolated from all other gametophytes. several days after a rainstorm, a sporophyte began to grow from an archegonium. what could you predict would be the case about the genetics of this sporophyte?

If a fern gametophyte is completely isolated and produces a sporophyte several days after a rainstorm, the sporophyte would have arisen from fertilization involving gametes produced by that single gametophyte. This process is called intragametophytic selfing, where sperm fertilize an egg on the same gametophyte. Because the gametophyte is haploid and produces genetically identical gametes, the resulting sporophyte would be diploid but completely homozygous at all gene loci, meaning it would have two identical copies of each gene inherited from the same gametophyte parent. This homozygosity occurs because both the sperm and egg come from the same haploid genome, so the sporophyte's genetics reflect a doubling of that single set of genes

. In summary:

• The sporophyte would be genetically homozygous.
• It would inherit all its genes from the single isolated gametophyte.
• This results from intragametophytic self-fertilization where sperm fertilize eggs on the same gametophyte