Construction of a nurse shark (Ginglymostoma cirratum) bacterial artificial chromosome (BAC) library and a preliminary genome survey.
BACKGROUND
Sharks are members of the taxonomic class Chondrichthyes, the oldest living jawed vertebrates. Genomic studies of this group, in comparison to representative species in other vertebrate taxa, will allow us to theorize about the fundamental genetic, developmental, and functional characteristics in the common ancestor of all jawed vertebrates.


OBJECTIVE
In order to obtain mapping and sequencing data for comparative genomics, we constructed a bacterial artificial chromosome (BAC) library for the nurse shark, Ginglymostoma cirratum.


RESULTS
The BAC library consists of 313,344 clones with an average insert size of 144 kb, covering ~4.5 x 1010 bp and thus providing an 11-fold coverage of the haploid genome. BAC end sequence analyses revealed, in addition to LINEs and SINEs commonly found in other animal and plant genomes, two new groups of nurse shark-specific repetitive elements, NSRE1 and NSRE2 that seem to be major components of the nurse shark genome. Screening the library with single-copy or multi-copy gene probes showed 6-28 primary positive clones per probe of which 50-90% were true positives, demonstrating that the BAC library is representative of the different regions of the nurse shark genome. Furthermore, some BAC clones contained multiple genes, making physical mapping feasible.


CONCLUSIONS
We have constructed a deep-coverage, high-quality, large insert, and publicly available BAC library for a cartilaginous fish. It will be very useful to the scientific community interested in shark genomic structure, comparative genomics, and functional studies. We found two new groups of repetitive elements specific to the nurse shark genome, which may contribute to the architecture and evolution of the nurse shark genome.
Luo
Meizhong
M
Arizona Genomics Institute, Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA. mzluo@mail.hzau.edu.cn
Kim
Hyeran
H
Kudrna
Dave
D
Sisneros
Nicholas B
NB
Lee
So-Jeong
SJ
Mueller
Christopher
C
Collura
Kristi
K
Zuccolo
Andrea
A
Buckingham
E Bryan
EB
Grim
Suzanne M
SM
Yanagiya
Kazuyo
K
Inoko
Hidetoshi
H
Shiina
Takashi
T
Flajnik
Martin F
MF
Wing
Rod A
RA
Ohta
Yuko
Y