Dosage compensation in birds

H A McQueen, D McBride, G Miele, A P Bird, M Clinton

Research output: Contribution to journalArticlepeer-review

Abstract

The Z and W sex chromosomes of birds have evolved independently from the mammalian X and Y chromosomes [1]. Unlike mammals, female birds are heterogametic (ZW), while males are homogametic (ZZ). Therefore male birds, like female mammals, carry a double dose of sex-linked genes relative to the other sex. Other animals with nonhomologous sex chromosomes possess "dosage compensation" systems to equalize the expression of sex-linked genes. Dosage compensation occurs in animals as diverse as mammals, insects, and nematodes, although the mechanisms involved differ profoundly [2]. In birds, however, it is widely accepted that dosage compensation does not occur [3-5], and the differential expression of Z-linked genes has been suggested to underlie the avian sex-determination mechanism [6]. Here we show equivalent expression of at least six of nine Z chromosome genes in male and female chick embryos by using real-time quantitative PCR [7]. Only the Z-linked ScII gene, whose ortholog in Caenorhabditis elegans plays a crucial role in dosage compensation [8], escapes compensation by this assay. Our results imply that the majority of Z-linked genes in the chicken are dosage compensated.
Original languageEnglish
Pages (from-to)253-7
Number of pages5
JournalCurrent biology : CB
Volume11
Issue number4
Publication statusPublished - 2001

Keywords

  • Aconitate Hydratase/genetics
  • Actins/genetics
  • Animals
  • Avian Proteins
  • Birds/genetics
  • Chick Embryo
  • DNA-Binding Proteins/genetics
  • Dosage Compensation, Genetic
  • Female
  • Follistatin
  • Glycoproteins/genetics
  • Growth Hormone/genetics
  • Male
  • Nuclear Proteins/genetics
  • Sex Chromosomes
  • Transcription Factors/genetics

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