Andersson grew up in Horndal, Dalarna. Her mother was home care assistant and her father was employed in the wood industry.[6] She studied Biology at Uppsala University, since the programme was the only one that had a course about DNA. She defended her PhD in molecular biology in 1990, under the supervision of Charles Kurland.[7] She applied for a postdoctoral stipend from EMBO to continue her research in the United States, but ended up obtaining a research position at the MRC Laboratory of Molecular Biology in Cambridge.[6] She became professor of molecular evolution in 2000, at the Uppsala University's Evolutionary Biology Center.[6] She was elected at the Royal Swedish Academy of Sciences in 2005.[2]
Andersson has been very active in developing the Swedish national center for large-scale research Science for Life Laboratory, especially its DNA sequencing and bioinformatics platforms. She served as Co-director for the center between 2017 and 2021.[5]
Andersson's research first focused around the role of codon usage in shaping bacterial genomes.[10] After her postdoctoral fellowship, she contributed to sequence one of the first genome of an obligate intracellular parasite, Rickettsia prowazekii, the causative agent of epidemic typhus.[11]
In her later career, her research continued to explore bacteria and their relationships with their different hosts.[12] In particular, she is interested in the genomic consequences of long-term associations of intracellular bacteria.[13] She explored the evolution of Bartonella,[14]Wolbachia,[15] and Planctomycetota,[16] among others.
Andersson has published over 200 peer-reviewed articles, and has an h-index of 61, as of 2022.[17]
2002 - Letterstedtska prize for very significant investigation, among others for "an article in Nature (1998), which reports the whole genome sequence of the intracellular parasite Rickettsia prowazekii".[18]
^Sällström, B; Andersson, SG (October 2005). "Genome reduction in the alpha-Proteobacteria". Current Opinion in Microbiology. 8 (5): 579–85. doi:10.1016/j.mib.2005.08.002. PMID16099701.