Comprehensive search for chicken W chromosome-linked genes expressed in early female embryos from the female-minus-male subtracted cDNA macroarray

Abstract

In order to seek chicken W chromosome-linked genes expressed significantly earlier than the time of gonadal differentiation, female-minus-male-subtracted cDNA macroarrays were prepared from day 2 (Hamburger-Hamilton stages 12-13), day 3 (stages 19-20) and day 4 (stages 24-25) embryos. From a total of 15-744 macroarrayed cDNA clones, 610 clones exhibiting significantly female-specific expression were selected. When each one of the 610 cDNA clones was used as a probe in Southern blot hybridization with male or female chicken genomic DNA, 62 clones, grouped into eight (A-H) types according to their patterns of hybridization, were considered to be derived from W chromosome-linked genes. When representative cDNA clones in each type were sequenced, clones derived from two known W-linked genes; SPIN-W and ATP5A1W , and from two hitherto unknown W-linked genes, represented by 2d-2D9 and 2d-2F9 clones, were identified and their localizations on the W chromosome were confirmed by fluorescence in-situ hybridization. The 2d-2D9 sequence has no significant homology with other genes in databases but 2d-2F9 has a region which shows partial homology to the consensus sequence of the AAA ATPase superfamily. Both 2d-2D9 and 2d-2F9 sequences are found in contigs of undetermined chromosome-linkage in the Draft Chicken Genome Sequence.

Differential expression of the MHM region and of sex-determining-related genes during gonadal development in chicken embryos

“…The highest level of HINTZ expression was noted in males at the HH40 stage (post-differentiation) and decreased in gonadal adult tissues of both sexes ( Figure 3B). Previous studies (Yamada et al, 2004) and our results showed low HINTW expression in gonadal regions, during the HH20, HH25, and HH28 stages ( Figure 3C). We describe here for the first time that HINTW expression in female gonads peaked at HH35.…”

Genetic evidence against a role for W-linked histidine triad nucleotide binding protein (HINTW) in avian sex determination

“…Expression is detectable as early as day 2.5 (Yamada et al, 2004), and it persists in the developing urogenital system, nervous system, somites and limbs. In the embryonic gonads, the gene is expressed at all stages that have been examined, from the time of gonadal formation (day 3), throughout sexual differentiation (from day 6), and up to hatching (Hori et al, 2000).…”

Bisexual branching processes to model extinction conditions for Y-linked genes

“…To avoid confusion, these sex chromosomes are deniminated Z and W. Thus in birds, snakes, and butterflies, for example, females have ZW sex chromosomes, and males have ZZ A c c e p t e d m a n u s c r i p t sex chromosomes. Now, Y-linked problems become W-linked (see, for example, Ogawa et al (1998), Yamada et al (2004), or Abe et al (2008)). For simplicity in notation, throughout this paper only the XX/XY sex determination system will be referred to, although the development and the results are equally valid for the ZZ/ZW system.…”