# Experimental genetic crosses for malaria research

> **NIH NIH P01** · UNIVERSITY OF NOTRE DAME · 2021 · $308,020

## Abstract

ABSTRACT
A concrete way to map genotypes that cause drug resistance phenotypes is by performing a well thought out
experimental genetic cross between drug resistance and drug susceptible Plasmodium falciparum strains,
isolating recombinant progeny and then using quantitative trait loci mapping to link genotype to phenotype. Three
P. falciparum genetic crosses were carried out in splenectomized chimpanzees over 23 years and one of the
great achievements of these crosses was the genetic determinant of chloroquine resistance – point mutations in
the pfcrt gene. The NIH has now banned chimpanzee research for financial and ethical reasons but we have
developed a human-liver chimeric mouse model (the FRG huHep mouse) to replace the chimpanzee for the
generation of recombinant progeny from P. falciparum genetic crosses.
The FRG mouse lacks the fumaryl acetoacetate hydrolase gene (F designation) and this causes hepatocyte cell
death. However, hepatocyte death is controlled with the drug nitisinone. Since only mouse hepatocytes lack
fumaryl acetoacetate hydrolase, this enables repopulation of the mouse with human hepatocytes over time with
on-off drug use to control the death of mouse hepatocytes and their replacement with human hepatocytes. In
close collaboration with the Yecuris Corporation, who creates the FRG huHep mouse, we ensure that the mice
we use for our studies have maximal human hepatocyte chimerism and are susceptible to P. falciparum
sporozoite infection. Additionally, the mice are able to maintain a human red blood cell (huRBC) population after
huRBC infusion and this allows for P. falciparum liver stage-to-blood stage transition in the mouse. Following
blood removal, the in vitro expansion of asexual P. falciparum blood stages allows for downstream cloning and
then –omics analyses and phenotypic analyses of recombinant progeny.
We have already demonstrated our ability to use the FRG huHep/huRBC mouse for the generation of
recombinant progeny from experimental crosses and Core A will isolate recombinant progeny from a further
eight well conceived experimental genetic crosses between P. falciparum drug resistant and drug susceptible
strains as part of this P01. The success of Core A will be aided by RP01 in efforts to maximize the number
unique progeny from each cross. Additionally, RP01 will work closely with Core A to determine if bulk segregant
analysis coupled with whole genome sequencing can speed the time taken to link genotype to phenotype. The
phenotyping of progeny supplied by Core A and downstream mapping of genetic loci responsible for observed
phenotypes are integral parts of RP01, RP02 & RP03 and such Core A is the linchpin of this P01. Successful
creation of progeny for this P01 will further our understanding of the spread of artemisinin drug resistance and
the emergence of piperaquine drug resistance.

## Key facts

- **NIH application ID:** 10216643
- **Project number:** 5P01AI127338-05
- **Recipient organization:** UNIVERSITY OF NOTRE DAME
- **Principal Investigator:** Ashley M Vaughan
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $308,020
- **Award type:** 5
- **Project period:** 2017-08-01 → 2024-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10216643

## Citation

> US National Institutes of Health, RePORTER application 10216643, Experimental genetic crosses for malaria research (5P01AI127338-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10216643. Licensed CC0.

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