Testing the flexibility of dosage compensation by mimicking the initial and turn-over stages of sex chromosomes

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H02539
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 45020:Evolutionary biology-related
• Research Institution: Tokyo Metropolitan University
• Principal Investigator: Nozawa Masafumi 東京都立大学, 理学研究科, 准教授 (50623534)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 遺伝子量補償 / ショウジョウバエ / 性染色体 / 遺伝子発現 / 性染色体サイクル

Outline of Final Research Achievements

In this research, immediacy and flexibility of dosage compensation (DC) was tested by using Drosophila miranda with neo-sex chromosomes. To mimic the state just after the losses of the Y-linked genes, heavy-ion beams were irradiated to males and F1 males derived from the irradiated males were obtained. Because the frequency of deletions on 1:1 gametologs was significantly lower than multi-copy genes on the neo-Y, immediate DC in one generation unlikely operates on the neo-X. In addition, I mimicked the status just after sex-chromosome turnover by crossing D. miranda with its closely related species without neo-sex chromosomes and making hybrids. Using the genes that are least affected by hybrid incompatibility, I found that DC was considerably weakened on the "previous" X chromosome.

Free Research Field

ゲノム進化学、分子進化学

Academic Significance and Societal Importance of the Research Achievements

性染色体進化において多くの種に見られる遺伝子量補償がY染色体の退化に伴ってどのくらい迅速に作用するのか、そして性染色体が常染色体に戻る際、遺伝子量補償がどのくらい柔軟に消失するのかという、性染色体進化における重要な2つの事象を模倣する実験系を確立できたことは意義のあることであると考えている。性染色体がただ退化するだけの染色体ではなく、潜在的に常染色体にも再転換しうることを実験的に示す道筋を示せたことも重要であると考えている。