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Dissertation Information for Takuya Nakazato

NAME:
- Takuya Nakazato

DEGREE:
- Ph.D.

DISCIPLINE:
- Biology

SCHOOL:
- Indiana University (USA) (2005)

ADVISORS:
- Gerald Gastony

COMMITTEE MEMBERS:
- Beverly Pfeifer Lynch
- Michael J. Wade
- Loren H. Riesberg
- Jeffrey Palmer

MPACT Status: Incomplete - Not_Inspected

Title: Genetic map-based analysis of genome structure in Ceratopteris richardii

Abstract: A genetic linkage map of a homosporous fern model species, Ceratopteris richardii , was constructed based on 729 AFLP, RFLP, or isozyme markers. Forty one linkage groups partly corresponding to 39 chromosomes of this species were detected with average spacing between markers of 3.18 cM. The large number of duplicated gene copies detected on the Southern blots, many on different chromosomes, indicates that as in other eukaryotic genomes, gene duplication plays a prominent role in shaping the genome architecture of this species. Although past polyploidization is a potential mechanism for the observed abundance of gene duplicates, the absence of large syntenic regions consisting of duplicated gene copies suggests that small-scale duplications may be the primary mode of gene duplication in C. richardii . Alternatively, evidence of past polyploidization(s) may be masked by extensive chromosomal rearrangements and small-scale duplications following polyploidization(s). A large number of markers throughout the genome showed significant deviation of allele frequencies from neutral expectations (Transmission Ratio Distortion, TRD) in various degrees and toward both parents. This pattern of TRD is most consistent with gradual accumulation of the genetic factors responsible for the reproductive barrier between the two parental populations of our cross since their divergence. Several genomic regions responsible for several morphological trait differences (Quantitative Trait Loci, QTLs) between the parents of the cross were detected. The absence of QTLs with major effects once again implies gradual changes in the genetic factors causing the trait differences. The first linkage map of a fern genome produced by this study should provide resources and genetic tools to make C. richardii a useful non-angiosperm model system for genetic studies. This study also provides a foundation for future studies investigating the evolution of homosporous ferns and vascular plants in general.

MPACT Scores for Takuya Nakazato

A = 0
C = 0
A+C = 0
T = 0
G = 0
W = 0
TD = 0
TA = 0
calculated 2010-10-14 00:12:43

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