Dosage compensation in birds

McQueen, Heather; McBride, Derek; Miele, Gino; Bird, Adrian; Clinton, Michael

doi:10.1016/s0960-9822(01)00070-7

Cited by 111 publications

(86 citation statements)

References 22 publications

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“…It seems clear that Z chromosome inactivation does not occur (Schmid et al 1989). There are reports of equalized expression levels in males and females for a limited number of Z-linked genes (Kuroda et al 2001;McQueen et al 2001), possibly regulated at the level of transcription since both Z chromosomes of male chicken are transcribed (Kuroda et al 2001;Kuroiwa et al 2002). The observations of a heterogeneous, noncoding RNA that accumulates on the Z chromosome in the female nucleus but is heavily Figure 3.…”

Section: Discussionmentioning

confidence: 98%

Genetic Mapping in a Natural Population of Collared Flycatchers (Ficedula albicollis): Conserved Synteny but Gene Order Rearrangements on the Avian Z Chromosome

Backström¹,

Brandström²,

Gustafsson

et al. 2006

Genetics

100

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Data from completely sequenced genomes are likely to open the way for novel studies of the genetics of nonmodel organisms, in particular when it comes to the identification and analysis of genes responsible for traits that are under selection in natural populations. Here we use the draft sequence of the chicken genome as a starting point for linkage mapping in a wild bird species, the collared flycatcher-one of the most well-studied avian species in ecological and evolutionary research. A pedigree of 365 flycatchers was established and genotyped for single nucleotide polymorphisms in 23 genes selected from (and spread over most of ) the chicken Z chromosome. All genes were also found to be located on the Z chromosome in the collared flycatcher, confirming conserved synteny at the level of gene content across distantly related avian lineages. This high degree of conservation mimics the situation seen for the mammalian X chromosome and may thus be a general feature in sex chromosome evolution, irrespective of whether there is male or female heterogamety. Alternatively, such unprecedented chromosomal conservation may be characteristic of most chromosomes in avian genome evolution. However, several internal rearrangements were observed, meaning that the transfer of map information from chicken to nonmodel bird species cannot always assume conserved gene orders. Interestingly, the rate of recombination on the Z chromosome of collared flycatchers was only 50% that of chicken, challenging the widely held view that birds generally have high recombination rates.

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Section: Discussionmentioning

confidence: 98%

Genetic Mapping in a Natural Population of Collared Flycatchers (Ficedula albicollis): Conserved Synteny but Gene Order Rearrangements on the Avian Z Chromosome

Backström¹,

Brandström²,

Gustafsson

et al. 2006

Genetics

100

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“…Recent quantitative RT-PCR data, however, show expression equalisation of several Z-linked genes in male and female chicken embryos. (65) Meanwhile, a separate study using fluorescent in situ hybridisation to nascent mRNAs has shown that these Z-linked genes are transcribed from both Z chromosomes in male cells. (66) Therefore, if dosage compensation does occur, it does not involve widespread inactivation of one sex chromosome, as occurs in mammals.…”

Section: Dmrt1 and The Z Dosage Hypothesismentioning

confidence: 99%

Sex determination: insights from the chicken

2004

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SummaryNot all vertebrates share the familiar system of XX:XY sex determination seen in mammals. In the chicken and other birds, sex is determined by a ZZ:ZW sex chromosome system. Gonadal development in the chicken has provided insights into the molecular genetics of vertebrate sex determination and how it has evolved. Such comparative studies show that vertebrate sex-determining pathways comprise both conserved and divergent elements. The chicken embryo resembles lower vertebrates in that estrogens play a central role in gonadal sex differentiation. However, several genes shown to be critical for mammalian sex determination are also expressed in the chicken, but their expression patterns differ, indicating functional plasticity. While the genetic trigger for sex determination in birds remains unknown, some promising candidate genes have recently emerged. The Z-linked gene, DMRT1, supports the Z-dosage model of avian sex determination. Two novel W-linked genes, ASW and FET1, represent candidate female determinants.

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“…Hypothetically, it is governed either by a dominant gene linked to the Wchromosome or by the amount of Z-chromosome dosage (Ellegren, 2000). On the basis of the studies that suggest the existence of compensation system for Z-chromosome linked genes (McQueen et al, 2001), the latter mechanism is less probable than the former.…”

Section: Introductionmentioning

confidence: 99%

Isolation of chicken homolog of the FOXL2 gene and comparison of its expression patterns with those of aromatase during ovarian development

Govoroun

Pannetier

Pailhoux

et al. 2004

Developmental Dynamics

192

119

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Mutations in the forkhead transcription factor gene FOXL2 are involved in ovarian failure, which occurs in human BPES syndrome. This syndrome presents a sexually dimorphic expression, specific to the ovary in several vertebrates. We cloned the open reading frame of chicken FOXL2 (cFoxL2) and studied cFoxL2 expression in developing gonads and during adulthood to examine the role of FOXL2 in ovarian differentiation and function in birds. The spatial and temporal dynamics of cFoxL2 and aromatase expression were analyzed in parallel by using real-time quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry in attempt to investigate the possible role of cFoxL2 in the regulation of aromatase. The expression patterns of cFoxL2 and aromatase transcripts were highly correlated during the sex-differentiation period (4.7-12.7 days of incubation). Aromatase and cFoxL2 proteins were colocalized in the medullar part of female gonads on embryonic day 14. Fourteen days after hatching, cFoxL2 protein was mainly detected in granulosa cells of developing follicles. In adult ovary follicular envelopes, apart from granulosa cells, cFoxL2 transcript and protein were detected at lower levels in theca cells where aromatase was present. A high level of cFoxL2 transcription was also observed in maturing and ovulated oocytes. Our results confirm that FoxL2 is an early regulator of ovarian development in birds and may be involved in aromatase transcription regulation. Developmental Dynamics 231:859 -870, 2004.

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Dosage compensation in birds

Cited by 111 publications

References 22 publications

Genetic Mapping in a Natural Population of Collared Flycatchers (Ficedula albicollis): Conserved Synteny but Gene Order Rearrangements on the Avian Z Chromosome

Genetic Mapping in a Natural Population of Collared Flycatchers (Ficedula albicollis): Conserved Synteny but Gene Order Rearrangements on the Avian Z Chromosome

Sex determination: insights from the chicken

Isolation of chicken homolog of the FOXL2 gene and comparison of its expression patterns with those of aromatase during ovarian development

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