She said a study in the United States earlier this year had estimated the incidence at one in 88.
"That's another reason why we need to get on and understand the disorder, the prevalence seems to be rising. It affects a huge portion of the population."
Her research involves analysing DNA from blood and saliva samples taken from people who have been diagnosed with autism spectrum disorder, looking for genetic mutations or variations and linking them to clinical descriptions of the patients written by their doctors.
"It's quite a complex disorder. The latest sequencing techniques have made it possible to look at the whole genome simultaneously, instead of just small sections at a time. That's allowed us to look at more complex disorders.
"Autism spectrum disorder has several genes that appear to be involved."
Similar gene studies to hers have been carried out overseas but it was important to do the work here too.
"I was keen to do it with the New Zealand population which has these unique population groups and well-characterised samples.
"We have these well-described patient samples, which makes relating the genetics that we find back to what the clinical presentation of the disease is much easier.
"It means when you find a mutation in a gene or a variant in a gene, if that gene is involved in something particular, you can look back at the clinical presentation and see if that particular patient had a more severe form ..."
There is no cure for autism, but various therapies can be used to help manage some of the symptoms.
Dr Jacobsen said she hoped her research would lead to better therapies and educational support systems.
Each fellowship provides $160,000 a year, which goes towards the researcher's salary and programme of work.
The Royal Society said the fellowships were aimed at developing and fostering the future leaders of New Zealand science and innovation.
Science and Innovation Minister Steven Joyce said high-quality research was the cornerstone of innovation and key to expanding the economy.
"The scheme aims to help accelerate the development of researchers who have been recognised for excellence within their respective disciplines."
The other nine
* Dr Geoff Willmott, Industrial Research. To develop new tools to manipulate fluids at the sub-micro "nano-fluid" level.
* Dr Lara Shepherd, Te Papa museum. Will investigate domestication and decline of several New Zealand plant species, dating from pre-European times.
* Dr Nicholas Rattenbury, Auckland University. Looking for Earth-like planets orbiting stars elsewhere in the universe.
* Dr Martin Allen, Canterbury University. Will study new semiconductor materials such as zinc oxide, trying to design new tools to assess risks and benefits of ultraviolet radiation to human health.
* Clemency Montelle, Canterbury University. Will analyse Sanskrit works and artefacts to understand ancient Indian maths and astronomy.
* Dr Shinichi Nakagawa, Otago University, Zoology. To study how and why genetic and physical diversity is maintained.
* Dr Peter Mace, Otago University, Medicine. Looking at molecular signalling mechanisms at the border between cellular life and death.
* Dr Timothy Woodfield, Otago University. Mixing engineering, biology and medicine to find new ways to regenerate bone and cartilage to fix damaged joints.
* Dr Barbara Anderson, Otago University. She aims to disentangle the roles of ecology and evolution in how species respond to climate change.
