| genetic drift outweighs balancing selection in shaping post-bottleneck major histocompatibility complex variation in new zealand robins (petroicidae). | the chatham island black robin, petroica traversi, is a highly inbred, endangered passerine with extremely low levels of variation at hypervariable neutral dna markers. in this study we investigated variation in major histocompatibility complex (mhc) class ii genes in both the black robin and its nonendangered relative, the south island robin petroica australis australis. previous studies have shown that petroica have at least four expressed class ii b mhc genes. in this study, the sequences of ... | 2004 | 15548285 |
| gene duplication and gene conversion in class ii mhc genes of new zealand robins (petroicidae). | in contrast to mammals, the evolution of mhc genes in birds appears to be characterized by high rates of gene duplication and concerted evolution. to further our understanding of the evolution of passerine mhc genes, we have isolated class ii b sequences from two species of new zealand robins, the south island robin (petroica australis australis), and the endangered chatham island black robin (petroica traversi). using an rt-pcr based approach we isolated four transcribed class ii b mhc sequence ... | 2004 | 15138734 |
| a molecular phylogeny of new zealand's petroica (aves: petroicidae) species based on mitochondrial dna sequences. | the new zealand robin (petroica australis), tomtit (p. macrocephala), and chatham island black robin (p. traversi) are members of the petroicidae family of australo-papuan robins, found throughout australasia and the western pacific. in the nearly 200 years since the new zealand members of petroicidae were first described, the division of species, subspecies, and even genera has undergone many changes. in this study, we investigate whether molecular phylogenies based on mitochondrial dna sequenc ... | 2006 | 16750641 |
| severe inbreeding depression and no evidence of purging in an extremely inbred wild species--the chatham island black robin. | although evidence of inbreeding depression in wild populations is well established, the impact of genetic purging in the wild remains controversial. the contrasting effects of inbreeding depression, fixation of deleterious alleles by genetic drift, and the purging of deleterious alleles via natural selection mean that predicting fitness outcomes in populations subjected to prolonged bottlenecks is not straightforward. we report results from a long-term pedigree study of arguably the world's most ... | 2014 | 24303793 |
| how old is this bird? the age distribution under some phase sampling schemes. | in this paper, we use a finite-state continuous-time markov chain with one absorbing state to model an individual's lifetime. under this model, the time of death follows a phase-type distribution, and the transient states of the markov chain are known as phases. we then attempt to provide an answer to the simple question "what is the conditional age distribution of the individual, given its current phase"? we show that the answer depends on how we interpret the question, and in particular, on th ... | 2017 | 28374100 |