Carcass traits and fat quality of breeding emu (Dromaius novaehollandiae) in Northern Japan.

Characterization of carcass traits and fat quality is important to effectively produce and genetically improve emus. We investigated carcass traits in 309 emus. The meat production of female emus showed a significantly higher value than that of males (P < 0.01). The fat weight of male (9.232 ± 3.156 kg) was larger than that of the female (7.772 ± 2.697 kg). The fat yield (fat weight per kg of body weight) was strongly correlated to body weight (r = 0.79 and r = 0.75 in male and female, respectively). The fat melting points of females and males were 19.19 ± 3.39°C and 19.39 ± 3.39°C, respectively, without significant difference. Since the fat melting point did not correlate to body and fat weights, we predicted that it was an independent trait from body growth and was highly influenced by genetic elements. Percentages of palmitic, stearic, oleic, linoleic, and α-linolenic acids were 22.27 ± 3.50%, 9.37 ± 1.90%, 54.11 ± 5.17%, 13.54 ± 7.80% and 0.71 ± 0.59%, respectively. Among them, linoleic acid contents showed a wide individual difference (range 0.3-19.9%). The oleic/stearic acid ratio showed a negative correlation to the fat melting point. These results suggest that the fat melting point is a good indicator of C18:1/C18:0 ratio in emu fat.

A deletion in a cis element of Foxe3 causes cataracts and microphthalmia in rct mice.

The Rinshoken cataract (rct) mutation, which causes congenital cataracts, is a recessive mutation found in SJL/J mice. All mutants present with opacity in the lens by 2 months of age. The rct locus was mapped to a 1.6-Mb region in Chr 4 that contains the Foxe3 gene. This gene is responsible for cataracts in humans and mice, and it plays a crucial role in the development of the lens. Furthermore, mutation of Foxe3 causes various ocular defects. We sequenced the genomic region of Foxe3, including the coding exons and UTRs; however, no mutations were discovered in these regions. Because there were no differences in Foxe3 sequences between the rct/rct and wild-type mice, we inferred that a mutation was located in the regulatory regions of the Foxe3 gene. To test this possibility, we sequenced a 5' noncoding region that is highly conserved among vertebrates and is predicted to be the major enhancer of Foxe3. This analysis revealed a deletion of 22-bp located approximately 3.2-kb upstream of the start codon of Foxe3 in rct mice. Moreover, we demonstrated by RT-PCR and in situ hybridization that the rct mutant has reduced expression of Foxe3 in the lens during development. We therefore suggest that cataracts in rct mice are caused by reduced Foxe3 expression in the lens and that this decreased expression is a result of a deletion in a cis-acting regulatory element.

Quantitative trait loci on chromosome 5 for susceptibility to frequency-specific effects on hearing in DBA/2J mice.

The DBA/2J strain is a model for early-onset, progressive hearing loss in humans, as confirmed in the present study. DBA/2J mice showed progression of hearing loss to low-frequency sounds from ultrasonic-frequency sounds and profound hearing loss at all frequencies before 7 months of age. It is known that the early-onset hearing loss of DBA/2J mice is caused by affects in the ahl (Cdh23(ahl)) and ahl8 (Fscn2(ahl8)) alleles of the cadherin 23 and fascin 2 genes, respectively. Although the strong contributions of the Fscn2(ahl8) allele were detected in hearing loss at 8- and 16-kHz stimuli with LOD scores of 5.02 at 8 kHz and 8.84 at 16 kHz, hearing loss effects were also demonstrated for three new quantitative trait loci (QTLs) for the intervals of 50.3-54.5, 64.6-119.9, and 119.9-137.0 Mb, respectively, on chromosome 5, with significant LOD scores of 2.80-3.91 for specific high-frequency hearing loss at 16 kHz by quantitative trait loci linkage mapping using a (DBA/2J × C57BL/6J) F1 × DBA/2J backcross mice. Moreover, we showed that the contribution of Fscn2(ahl8) to early-onset hearing loss with 32-kHz stimuli is extremely low and raised the possibility of effects from the Cdh23(ahl) allele and another dominant quantitative trait locus (loci) for hearing loss at this ultrasonic frequency. Therefore, our results suggested that frequency-specific QTLs control early-onset hearing loss in DBA/2J mice.

Expression analysis of the type I keratin protein keratin 33A in goat coat hair.

The coat of a goat, like that of many mammalian species, consists of an outer coat of coarse hairs and an under coat of fine, downy hairs. The coarse guard hairs are produced by primary follicles and the finer cashmere hairs by secondary follicles. We previously reported that hair keratins are components of cashmere hair, and proteomic analysis revealed that their expression is elevated in winter coat hair. To determine detailed characterization, we have cloned keratin 33A gene, a major highly expressed keratin in winter, and then analyzed the expression of goat hair coat. By Western analysis, we detected that keratin 33A protein is expressed only in hair coat among the various goat tissues. Moreover, the expression level in winter has increased in cashmere high-producing Korean native breed, whereas the expression levels between summer and winter had not changed in cashmere low-producing Saanen. In addition, by immunohistochemistry we determined that keratin 33A is localized in the major cortex portion of cashmere fiber. These results confirm that keratin 33A is a structural protein of goat cashmere hair fiber.

The complete mitochondrial genome of the domestic red deer (Cervus elaphus) of New Zealand and its phylogenic position within the family Cervidae.

We determined the complete nucleotide sequence of the mitochondrial genome of the semidomestic red deer (Cervus elaphus) of New Zealand. The genome was 16,357 bp long and contained 13 protein-coding genes, 12SrRNA, 16SrRNA, 22 tRNAs and a D-loop as found in other mammals. Database homology searches showed that the mitochondrial DNA (mtDNA) sequence from the New Zealand semidomestic deer was similar to partial mtDNA sequences from the European, Norwegian (C. e. atlanticus) and Spanish red deer (C. e. hispanicus). Phylogenetic analysis of the mitochondrial protein-coding regions revealed two well-defined monophyletic clades in subfamilies Cervinae and Muntiacinae. However, red deer and Sika deer were not found to be close relatives. The analysis did identify the red deer as a sister taxon of a Samber/Sika deer clade, although it was more closely related to the Samber than the Sika group.

Protein 4.1 expression in the developing hair cells of the mouse inner ear.

Protein 4.1 (band 4.1 or 4.1R) was originally identified as an abundant protein of the human erythrocyte, in which it stabilizes the spectrin/actin cytoskeleton. Subsequently, several new family members, 4.1N, 4.1G and 4.1B, have been identified, which are expressed in many cell types, in particular at cell-cell junctions. We previously reported that 4.1R and 4.1N are expressed in the inner ear hair cells with specific localization patterns, and that 4.1R forms a complex with the membrane-associated guanylate kinase (MAGUK) protein p55 and two deafness gene products, myosin XV and whirlin. To determine the functions of the other family members, 4.1G and 4.1B, we observed their expression patterns in developing stereocilia in mice inner ear hair cells. 4.1G is expressed in the basal tapers of the stereocilia bundle in early postnatal stages. 4.1B was specifically and constantly expressed in the stereocilia tips during postnatal development. Additionally, we found that 4.1B is ablated in the hair cells of both myosin XV and whirlin mutant mice at all stages in hair cell development. These results suggest that 4.1 family members play important roles in the development and maintenance of the inner ear hair cells, and that 4.1B may be a member of the myosin XV-whirlin complex that is important for stereocilia maturation.

Phenotypic and expression analysis of a novel spontaneous myosin VI null mutant mouse.

In humans, hearing is a major factor in quality of life. Mouse models are important tools for the discovery of genes responsible for genetic hearing loss, often enabling analysis of the processes that regulate the onset of deafness in humans. Thus far, at least 400 deafness mutants have been discovered in laboratory mouse populations and used in the study of deafness. Here we report the discovery of a new spontaneous recessive Rinshoken shaker/waltzer (rsv) mutant derived from our in-house C57BL/6J stock, which exhibits circling and/or head-tossing behaviour and complete lack of auditory brain response to any sound pressure. The hearing and balance phenotypes are associated with structural defects, in particular, disorganisation and fusion of stereocilia in the inner ear hair cells. Two sets of intersubspecific N(2) mice were generated for the positional cloning of the rsv mutation. The mutant locus was mapped to a 4.8-Mb region of chromosome 9, which contains myosin VI (Myo6), a gene responsible for deafness in humans and Snell's waltzer mutation in mice. The rsv mutant showed reduced expressions of Myo6 mRNA and MYO6 protein in the inner ear. Moreover, no immunoreactivity was observed in the cochlear and vestibular hair cells in the rsv mutant mice. We sequenced the genomic region (30,154 bp) of Myo6, including all coding exons, a non-coding exon, UTRs and the Myo6 promoter; however, no mutation was discovered in these regions. We therefore speculate that loss of MYO6 expression might cause shaker/waltzer behaviour and deafness in the rsv mutant; also, loss of MYO6 expression might be the result of mutations in an unidentified regulatory region(s) of the gene.