Katelyn Flitcroft, “Quantifying Inbreeding Depression in Nereocystis luetkeana”
Mentor: Filipe Alberto, Biological Sciences
Poster #49

Recent Landsat satellite imagery has documented significant decline in Bull Kelp forests, Nereocystis luetkeana, in regions of northern California, Washington, and Oregon due to climate change and marine heatwaves. Kelp forests are biologically productive ecosystems for marine wildlife and human application. N. luetkeana, like other kelps, has a biphasic life cycle, the alternation of haploid gametophyte and diploid sporophyte phases that interact independently with the surrounding environment. This biphasic life cycle can result in self fertilization, the fusion of male and female gametes produced by the same sporophyte, which in turn could reduce the average fitness of progeny by inbreeding depression. Inbreeding depression, the reduced survival and fertility of offspring from inbred mating, is caused by the increased homozygosity of an individual for recessive deleterious alleles. Recent research has suggested that species who frequently self fertilize tend to have decreased levels of inbreeding depression due to “purging” (removal) of the recessive deleterious alleles in populations. Understanding whether inbreeding depression is present is important in conservation programs when restoration might fail to produce populations with high genetic diversity and effective population size. Species with low to none inbreeding depression are expected to be less impacted than those with high inbreeding depression. Comparisons of fitness will be made between offspring produced by self fertilization and outcrossing with specially selected individuals from our germplasm collection. The magnitude of fitness will be assessed through variables of initial growth rates, number of eggs produced, and number of sporophytes produced. Once the experiment is conducted, the sporophytes will be shipped to Mike Graham Facility in California for further research and measurements of traits. Because selfing is frequent in N. luetkeana mating system, self-fertilized and outcrossed crosses will show similar fitness due to the purging of recessive deleterious alleles in natural populations of N. luetkeana.