Plant Genome Outreach to Native Americans

Maize Segregation Distortion

More than 18,000 maize accessions are maintained by the NCRPIS. To ensure preservation of the original genetic profile of populations, stocks are propagated using the following methods. A balanced sample from 100 ears provides the seed for planting. For populations, those plants are non-reciprocally sibbed such that each plant is used once as a male or female. Inbred lines are typically self-pollinated. The Abnormal Chromosome 10 (Ab10) causes segregation distortion during female meiosis, preferentially transmitting knobs and linked loci to the next generation. Its presence could impact efforts to preserve a population dynamics status quo. We are working to develop SSR markers to screen populations for the presence of Ab10. In those populations where Ab10 is discovered, we will determine the proportions of individuals (1) homozygous for the normal chromosome 10 (N10), (2) heterozygous (N10/Ab10), and (3) homozygous for Ab10. We also will determine the chromosome 10 constitutions of samples from prior (and potentially future) generations. Results from these analyses will permit us to determine, for Ab10 containing populations, whether the propagation methods used ensure preservation of genetic profile over time or allow the proportions of knobs and linked loci to increase.

To view the SSR markers we screened, click the link to Browse Data to the left.