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- All Subjects: Marmosets
- Creators: Labban, Kyle John
- Creators: Nash, Leanne
Description
As an evolutionary force, hybridization outcomes include introgression, admixture, speciation, and reproductive isolation. While hybridization has been studied in several primates, the marmoset genus Callithrix is an important, but little studied example of Neotropical hybridization. Varying degrees of reproductive isolation exist between Callithrix species, and hybridization occurs at species borders or regions containing introduced and native species. Interbreeding between Callithrix species carries important implications for biodiversity and genetic integrity within the genus. However, species origins and levels of genetic admixture in marmoset hybrid zones are generally unknown, and few population genetic studies of individual Callithrix species exist. Using the mitochondrial control region and 44 microsatellite markers, this work explored the genetic diversity and species origins of two C. penicillata and C. jacchus hybrid zones, as well as genetic diversity and divergence in the parental species. Both marker types showed that C. penicillata is more genetically diverse than C. jacchus. Based on mtDNA, C. jacchus seems to have experienced a past population expansion and C. penicillata evolved under constant population size. The data revealed the existence of a previously undocumented natural hybrid zone along the São Francisco River in NE Brazil and confirmed species origins of an anthropogenic zone in Rio de Janeiro state. The data also showed much lower levels of admixture and genetic diversity within the natural hybrid zone than in the anthropogenic zone. Further, the data suggested that the São Francisco River is an important geographic barrier to gene flow in the natural hybrid zone. On the other hand, admixture patterns within the anthropogenic hybrid zone suggested collapse of reproductive barriers, and the formation of a hybrid marmoset swarm. Thus, this work suggested different evolutionary dynamics in anthropogenic vs. natural animal hybrid zones. Restriction Associated DNA sequencing (RADseq) identified a large number of single nucleotide polymorphisms within C. jacchus and C. penicillata genomes. These preliminary data were used to measure intraspecific genomic diversity and interspecific divergence. In the future, RADseq will be used to study genus-wide diversity of Callithrix species, examine past and present marmoset demographic history, and applied to the evolutionary study of marmoset hybridization.
ContributorsMalukiewicz, Joanna (Author) / Stone, Anne C. (Thesis advisor) / Nash, Leanne (Committee member) / Rosenberg, Michael (Committee member) / Hedrick, Phil (Committee member) / Ruiz-Miranda, Carlo (Committee member) / Arizona State University (Publisher)
Created2013
Description
Head turning is a common sound localization strategy in primates. A novel system that can track head movement and acoustic signals received at the entrance to the ear canal was tested to obtain binaural sound localization information during fast head movement of marmoset monkey. Analysis of binaural information was conducted with a focus on inter-aural level difference (ILD) and inter-aural time difference (ITD) at various head positions over time. The results showed that during fast head turns, the ITDs showed significant and clear changes in trajectory in response to low frequency stimuli. However, significant phase ambiguity occurred at frequencies greater than 2 kHz. Analysis of ITD and ILD information with animal vocalization as the stimulus was also tested. The results indicated that ILDs may provide more information in understanding the dynamics of head movement in response to animal vocalizations in the environment. The primary significance of this experimentation is the successful implementation of a system capable of simultaneously recording head movement and acoustic signals at the ear canals. The collected data provides insight into the usefulness of ITD and ILD as binaural cues during head movement.
ContributorsLabban, Kyle John (Author) / Zhou, Yi (Thesis director) / Buneo, Christopher (Committee member) / Dorman, Michael (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05