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1.
The zebra finch (Taeniopygia guttata) has a large Z chromosome and highly condensed W chromosome. We used the random amplified polymorphic DNA (RAPD) polymerase
chain reaction (PCR) technique to isolate female-specific sequences ZBM1 and ZBM2. Southern blot hybridization to male and
female zebra finch genomic DNA suggested that these sequences were located on the W chromosome, although homologous sequences
appeared to be autosomal or Z-linked. Fluorescent in situ hybridization (FISH) using bacterial artificial chromosome (BAC)
clones corresponding to ZBM sequences showed hybridization to the whole W chromosome, suggesting that the BACs encode sequences
that are repeated across the entire W chromosome. Based on the sequencing of a ZBM repetitive sequence and Z chromosome derived
BAC clones, we demonstrate a random distribution of repeat sequences that are specific to the W chromosome or encoded by both
Z and W. The positions of ZW-common repeat sequences mapped to a noncoding region of a Z chromosome BAC clone containing the
CHD1Z gene. The apparent lineage-specificity of W chromosome repeat sequences in passerines and galliform birds suggest that
the W chromosome had not differentiated well from the Z at the time of divergence of these lineages.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
To clarify the process of avian sex chromosome differentiation in palaeognathous birds, we performed molecular and cytogenetic
characterization of W chromosome-specific repetitive DNA sequences for elegant crested tinamou (Eudromia elegans, Tinamiformes) and constructed comparative cytogenetic maps of the Z and W chromosomes with nine chicken Z-linked gene homologues
for E. elegans and ostrich (Struthio camelus, Struthioniformes). A novel family of W-specific repetitive sequences isolated from E. elegans was found to be composed of guanine- and cytosine-rich 293-bp elements that were tandemly arrayed in the genome as satellite
DNA. No nucleotide sequence homologies were found for the Struthioniformes and neognathous birds. The comparative cytogenetic
maps of the Z and W chromosomes of E. elegans and S. camelus revealed that there are partial deletions in the proximal regions of the W chromosomes in the two species, and the W chromosome
is more differentiated in E. elegans than in S. camelus. These results suggest that a deletion firstly occurred in the proximal region close to the centromere of the acrocentric
proto-W chromosome and advanced toward the distal region. In E. elegans, the W-specific repeated sequence elements were amplified site-specifically after deletion of a large part of the W chromosome
occurred. 相似文献
3.
We have developed a new marker (Z43B) that can be successfully used to identify the sex of most birds (69%), including species difficult or impossible to sex with other markers. We utilized the zebra finch Taeniopygia guttata EST microsatellite sequence (CK309496) which displays sequence homology to the 5′ untranslated region (UTR) of the avian spindlin gene. This gene is known to be present on the Z and W chromosomes. To maximize cross‐species utility, the primer set was designed from a consensus sequence created from homologs of CK309496 that were isolated from multiple distantly related species. Both the forward and reverse primer sequences were 100% identical to 14 avian species, including the Z chromosome of eight species and the chicken Gallus gallus W chromosome, as well as the saltwater crocodile Crocodylus porosus. The Z43B primer set was assessed by genotyping individuals of known sex belonging to 61 non‐ratite species and a single ratite. The Z and W amplicons differed in size making it possible to distinguish between males (ZZ) and females (ZW) for the majority (69%) of non‐ratite species tested, comprising 10 orders of birds. We predict that this marker will be useful for obtaining sex‐typing data for ca 6,869 species of birds (69% of non‐ratites but not galliforms). A wide range of species could be sex‐typed including passerines, shorebirds, eagles, falcons, bee‐eaters, cranes, shags, parrots, penguins, ducks, and a ratite species, the brown kiwi, Apteryx australis. Those species sexed include species impossible or problematic to sex‐type with other markers (magpie, albatross, petrel, eagle, falcon, crane, and penguin species). Zoo Biol. 35:533–545, 2016. © 2016 The Authors. Zoo Biology published by Wiley Periodicals, Inc. 相似文献
4.
Genes of the major histocompatibility complex (MHC) have received much attention in immunology, genetics, and ecology because
they are highly polymorphic and play important roles in parasite resistance and mate choice. Until recently, the MHC of passerine
birds was not well-described. However, the genome sequencing of the zebra finch (Taeniopygia guttata) has partially redressed this gap in our knowledge of avian MHC genes. Here, we contribute further to the understanding of
the zebra finch MHC organization by mapping SNPs within or close to known MHC genes in the zebra finch genome. MHC class I
and IIB genes were both mapped to zebra finch chromosome 16, and there was no evidence that MHC class I genes are located
on chromosome 22 (as suggested by the genome assembly). We confirm the location in the MHC region on chromosome 16 for several
other genes (BRD2, FLOT1, TRIM7.2, GNB2L1, and CSNK2B). Two of these (CSNK2B and FLOT1) have not previously been mapped in
any other bird species. In line with previous results, we also find that orthologs to the immune-related genes B-NK and CLEC2D,
which are part of the MHC region in chicken, are situated on zebra finch chromosome Z and not among other MHC genes in the
zebra finch. 相似文献
5.
We describe a karyotypic polymorphism on the zebra finch Z chromosome. This polymorphism was discovered because of a difference
in the position of the centromere and because it occurs at varying frequencies in domesticated colonies in the USA and Germany
and among two zebra finch subspecies. Using DNA fluorescent in situ hybridization to map specific Z genes and measurements of DNA replication, we show that this polymorphism is the result of
a large pericentric inversion involving the majority of the chromosome. We sequenced a likely breakpoint for the inversion
and found many repetitive sequences. Around the breakpoint, there are numerous repetitive sequences and several copies of
PAK3 (p21-activated kinase 3)-related sequences (PAK3Z) which showed testes-specific expression by RT-PCR. Our findings further suggest that the sequenced genome of the zebra finch
may be derived from a male heterozygote for the Z chromosome polymorphism. This finding, in combination with regional differences
in the frequency of the polymorphism, has important consequences for future studies using zebra finches. 相似文献
6.
Triploidy in a sexually dimorphic passerine provides new evidence for the effect of the W chromosome on secondary sexual traits in birds
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Crisley de Camargo H. Lisle Gibbs Mariellen C. Costa Luís F. Silveira Cláudia A. Rainho Paulo E. M. Ribolla Adriane P. Wasko Mercival R. Francisco 《Journal of avian biology》2017,48(11):1475-1480
In birds, there are two main models for the determination of sex: the ‘Z Dosage’ model in which the number, or dose, of Z chromosomes determines sex, and the ‘Dominant W’ model which argues that a specific gene in the W chromosome may influence Z gene expression and determine sex. The best evidence for W determination of sex comes from birds with 2 copies of the Z chromosome paired with a single W (e.g. ZZW) which are nonetheless females. Here, we expand the species where such a mechanism may operate by reporting a case of a triploid Neotropical passerine bird with sexually dimorphic plumage, the São Paulo marsh antwren Formicivora paludicola. Evidence from 17 autosomal unlinked microsatellite loci, and CHD1 sex‐linked locus, indicate that this individual is a 3n ZZW triploid with intermediate plumage pattern. This example expands our knowledge of sex determination mechanisms in birds by demonstrating that both the W and the two Z chromosomes affect the expression of morphological secondary sexual traits in a non‐galliform bird. 相似文献
7.
Neo-sex chromosomes often originate from sex chromosome–autosome fusions and constitute an important basis for the study of gene degeneration and expression in a sex chromosomal context. Neo-sex chromosomes are known from many animal and plant lineages, but have not been reported in birds, a group in which genome organization seems particularly stable. Following indications of sex linkage and unexpected sex-biased gene expression in warblers (Sylvioidea; Passeriformes), we have conducted an extensive marker analysis targeting 31 orthologues of loci on zebra finch chromosome 4a in five species, representative of independent branches of Passerida. We identified a region of sex linkage covering approximately the first half (10 Mb) of chromosome 4a, and associated to both Z and W chromosomes, in three Sylvioidea passerine species. Linkage analysis in an extended pedigree of one species additionally confirmed the association between this part of chromosome 4a and the Z chromosome. Markers located between 10 and 21 Mb of chromosome 4a showed no signs of sex linkage, suggesting that only half of the chromosome was involved in this transition. No sex linkage was observed in non-Sylvioidea passerines, indicating that the neo-sex chromosome arose at the base of the Sylvioidea branch of the avian phylogeny, at 47.4–37.6 millions years ago (MYA), substantially later than the ancestral sex chromosomes (150 MYA). We hypothesize that the gene content of chromosome 4a might be relevant in its transition to a sex chromosome, based on the presence of genes (for example, the androgen receptor) that could offer a selective advantage when associated to Z-linked sex determination loci. 相似文献
8.
Ellegren H 《EMBO reports》2001,2(3):192-196
The sex of an individual is generally determined genetically by genes on one of the two sex chromosomes. In mammals, for instance, the presence of the male-specific Y chromosome confers maleness, whereas in Drosophila melanogaster and Caenorhabditis elegans it is the number of X chromosomes that matters. For birds (males ZZ, females ZW), however, the situation remains unclear. The recent discovery that the Z-linked DMRT1 gene, which is conserved across phyla as a gene involved in sexual differentiation, is expressed early in male development suggests that it might be the number of Z chromosomes that regulate sex in birds. On the other hand, the recent identification of the first protein unique to female birds, encoded by the W-linked PKCIW gene, and the observation that it is expressed early in female gonads, suggests that the W chromosome plays a role in avian sexual differentiation. Clearly defining the roles of the DMRT1 and PKC1W genes in gonadal development, and ultimately determining whether avian sex is dependent on Z or W, will require transgenic experiments. 相似文献
9.
The molecular mechanism of sex determination in birds has long remained mysterious. Genetically male chicken embryos, which have two Z sex chromosomes, develop female gonads when the Z chromosome-linked gene DMRT1 is knocked out. This suggests that sex is determined by Z chromosome dosage. 相似文献
10.
Pigozzi MI 《Genetica》2011,139(6):771-777
All extant birds share the same sex-chromosome system: ZZ males and ZW females with striking differences in the stages of
sex-chromosome differentiation between the primitive palaeognathus ratites and the large majority of avian species grouped
within neognaths. Evolutionarily close to ratites is the neotropical order Tinamiformes that has been scarcely explored regarding
their ZW pair morphology and constitution. Tinamous, when compared to ratites, constitute a large group among Palaeognathae,
therefore, exploring the extent of homology between the Z and W chromosomes in this group might reveal key features on the
evolution of the avian sex chromosomes. We mapped MLH1 foci that are crossover markers on pachytene bivalents to determine
the size and localization of the homologous region shared by the Z and W chromosomes in two tinamous: Eudromia elegans and Crypturellus tataupa. We found that the homologous (pseudoautosomal) region differ significantly in size between these two species. They both
have a single recombination event on the long arm of the acrocentric Z and W chromosomes. However, in E. elegans the pseudoautosomal region occupies one-fourth of the W chromosome, while in C. tataupa it is restricted to the tip of the long arm of the W. The W chromosomes in these two species differ in their heterochromatin
content: in E. elegans it shows a terminal euchromatic segment and in C. tataupa is completely heterochromatic. These results show that tinamous have ZW pairs with more diversified stages of differentiation
compared to ratites. Finally, the idea that the avian proto-sex chromosomes started to diverge from the end of the long arm
towards the centromere of an acrocentric pair is discussed. 相似文献
11.
DEBORAH A. DAWSON JOHN CHITTOCK ROBERT JEHLE APRIL WHITLOCK DENISE NOGUEIRA JAYNE PELLATT TIM BIRKHEAD TERRY BURKE 《Molecular ecology resources》2005,5(2):298-301
Polymorphic microsatellite loci were identified in order to determine paternity in a captive population of the zebra finch, Taeniopygia guttata. Primer sets from 93 published passerine microsatellite sequences were tested for cross‐species amplification. Thirteen loci were found to be polymorphic, of which, eight displayed null alleles and one locus (Ase50) was found to be Z‐chromosome linked. 相似文献
12.
13.
ASW: a gene with conserved avian W-linkage and female specific expression in chick embryonic gonad 总被引:1,自引:0,他引:1
O'Neill M Binder M Smith C Andrews J Reed K Smith M Millar C Lambert D Sinclair A 《Development genes and evolution》2000,210(5):243-249
Vertebrates exhibit a variety of sex determining mechanisms which fall broadly into two classes: environmental or genetic.
In birds and mammals sex is determined by a genetic mechanism. In mammals males are the heterogametic sex (XY) with the Y
chromosome acting as a dominant determiner of sex due to the action of the testis-determining factor, SRY. In birds females
are the heterogametic sex (ZW); however, it is not known whether the W chromosome carries a dominant ovary-determining gene,
or whether Z chromosome dosage determines sex. Using an experimental approach, which assumes only that the sex-determining
event in birds is accompanied by sex-specific changes in gene expression, we have identified a novel gene, ASW (Avian Sex-specific W-linked). The putative protein for ASW is related to the HIT (histidine triad) family of proteins. ASW shows female-specific expression in genital ridges and maps to the chicken W chromosome. In addition, we show that, with
the exception of ratites, ASW is linked to the W chromosome in each of 17 bird species from nine different families of the class Aves.
Received: 18 October 1999 / Accepted: 10 January 2000 相似文献
14.
Küpper C Augustin J Edwards S Székely T Kosztolányi A Burke T Janes DE 《Biology letters》2012,8(5):787-789
Two models, Z Dosage and Dominant W, have been proposed to explain sex determination in birds, in which males are characterized by the presence of two Z chromosomes, and females are hemizygous with a Z and a W chromosome. According to the Z Dosage model, high dosage of a Z-linked gene triggers male development, whereas the Dominant W model postulates that a still unknown W-linked gene triggers female development. Using 33 polymorphic microsatellite markers, we describe a female triploid Kentish plover Charadrius alexandrinus identified by characteristic triallelic genotypes at 14 autosomal markers that produced viable diploid offspring. Chromatogram analysis showed that the sex chromosome composition of this female was ZZW. Together with two previously described ZZW female birds, our results suggest a prominent role for a female determining gene on the W chromosome. These results imply that avian sex determination is more dynamic and complex than currently envisioned. 相似文献
15.
DMRT1 in a ratite bird: evidence for a role in sex determination and discovery of a putative regulatory element 总被引:1,自引:0,他引:1
Unlike mammals, birds have a ZZ male/ZW female sex-determining system. In most birds, the Z is large and gene rich, whereas the W is small and heterochromatic, but the ancient group of ratite birds are characterized by sex chromosomes that are virtually homomorphic. Any gene differentially present on the ratite Z and W is therefore a strong candidate for a sex-determining role. We have cloned part of the candidate bird sex-determining gene DMRT1 from the emu, a ratite bird, and have shown that it is expressed during the stages of development corresponding to gonadal differentiation in the chicken. The gene maps to the distal region of the Z short arm and is absent from the large W chromosome. Because most sequences on the emu W chromosome are shared with the Z, the Z-specific location constitutes strong evidence that differential dosage of DMRT1 is involved in sex determination in all birds. The sequence of emu DMRT1 has 88% homology with chicken DMRT1 and 65% with human DMRT1. Unexpectedly, an unexpressed 270-bp region in intron 3 of emu DMRT1 showed 90% homology with a sequence in the corresponding intron of human DMRT1. This extraordinarily high conservation across 300 million years of evolution suggests an important function, perhaps involved in control of DMRT1 expression and vertebrate sex determination. 相似文献
16.
Carmichael AN Fridolfsson AK Halverson J Ellegren H 《Journal of molecular evolution》2000,50(5):443-447
Whether the mutation rate differs between sexes has been a matter of discussion for years. Molecular analyses of mammals
have indicated that males mutate more often than females, as manifested by the faster rate of neutral sequence evolution on
the Y chromosome than on the X chromosome. However, these observations can as well be interpreted as specific reduction of
the X chromosome mutation rate, which would be adaptive because of reducing the number of slightly deleterious recessive mutations
exposed in hemizygote males. Recently, data from birds have suggested that vertebrate mutation rates may indeed be male-biased.
In birds, females are the heterogametic sex (ZW), and analyses of the Z-linked CHD1Z gene have shown that it evolves faster
than its W-linked and thus female-specific homologue, CHD1W. We have now studied the second avian gene known to exist in a
copy on the nonrecombining regions of both the Z and the W chromosome, viz., the ATP synthase α-subunit (ATP5A1). In independent comparisons of three pairs of bird species from divergent lineages, intron
sequences of the Z-linked copy (ATP5A1Z) were consistently found to evolve faster than the W-linked copy (ATP5A1W). From these
data we calculated male-to-female mutation rate ratios (α) of 1.8, 2.3, and 5.0 in Galliform, Anseriform, and Ciconiiform
lineages, respectively. Therefore, this study provides independent support for a male-biased mutation rate in birds.
Received: 15 July 1999 / Accepted: 5 January 2000 相似文献
17.
Genes on the sex chromosomes are unique because of their sex-specific inheritance. One question is whether homologous gene pairs on the sex chromosomes, which have diverged in their sequence, have acquired different functions. We have analyzed the first homologous pair of genes (CHD1Z and CHD1W) discovered on the avian Z and W sex chromosomes of the zebra finch (Taeniopygia guttata) to examine whether functional differences may have evolved. Sequence analysis revealed that the two genes maintained a high degree of similarity especially within the C, H, and D domains, but outside of these regions larger differences were observed. Expression studies showed that CHD1W was unique to females and has the potential to produce a protein that CHD1Z does not. CHD1Z mRNA was expressed at a higher level in the male brain than in the female brain at various post-hatch ages. Reporter constructs containing the 5' flanking regions of each gene showed they had the ability to drive reporter expression in primary cell cultures. The 5' flanking region sequence of CHD1Z and CHD1W exhibited little homology, and differences in putative promoter elements were apparent. These differences between CHD1Z and CHD1W suggest that the two proteins may have diverged in their function. 相似文献
18.
Lih‐Chiann Wang Chi‐Tsong Chen Hsiao‐Yuan Lee Shou‐Hsien Li Jihn‐Tsair Lir Shin‐Chien Chin Chang‐En Pu Ching‐Ho Wang 《Zoo biology》2006,25(4):279-283
Sex determination of birds is important to ensure successful breeding strategies, especially for endangered species. Most birds are vulnerable to stress during handling, however, so obtaining a sufficient amount of genomic DNA (gDNA) while causing the least amount of harm is a critical issue. Avian gender can be determined based on different CHD1 gene intron sizes in W and Z sex chromosomes. We have compared various specimen sources and have found that the rachis segment of a feather is a good DNA source for determining sex. This indicates that plucking the whole feather is not necessary; a cut feather including the rachis is a superior method because it decreases stress on the examined birds and is accomplished easily. Zoo Biol. 0:1–5, 2006. © 2006 Wiley‐Liss, Inc. 相似文献
19.
20.
Christopher N Balakrishnan Robert Ekblom Martin Völker Helena Westerdahl Ricardo Godinez Holly Kotkiewicz David W Burt Tina Graves Darren K Griffin Wesley C Warren Scott V Edwards 《BMC biology》2010,8(1):1-19