Modelling the spatial spread of a homing endonuclease gene in a mosquito population

A mobile group I intron containing two ribozyme domains and a homing endonuclease gene (twin-ribozyme intron organization) can integrate by reverse splicing into the small subunit rRNA of bacteria and yeast. The integration is sequence-specific and corresponds to the natural insertion site (homing site) of the intron. The reverse splicing is independent of the homing endonuclease gene, but is dependent on the group I splicing ribozyme domain. The observed distribution of group I introns in nature can be explained by horizontal transfer between natural homing sites by reverse splicing and subsequent spread in populations by endonuclease-dependent homing.

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A CRISPR endonuclease gene drive reveals two distinct mechanisms of inheritance bias

10.1101/2020.12.15.421271 ◽

2020 ◽

Author(s):

Sebald A.N. Verkuijl ◽

Estela González ◽

Joshua Xin De Ang ◽

Ming Li ◽

Nikolay P Kandul ◽

...

Keyword(s):

Aedes Aegypti ◽

Homing Endonuclease ◽

Meiotic Drive ◽

Drive System ◽

Transgene Inheritance ◽

Gene Drive ◽

Tight Linkage ◽

Multiple Species ◽

Gene Drives ◽

Endonuclease Gene

RNA guided CRISPR gene drives have shown the capability of biasing transgene inheritance in multiple species. Among these, homing endonuclease drives are the most developed. In this study, we report the functioning of sds3, bgcn, and nup50 expressed Cas9 in an Aedes aegypti homing split drive system targeting the white gene. We report their inheritance biasing capability, propensity for maternal deposition, and zygotic/somatic expression. Additionally, by making use of the tight linkage of white to the sex-determining locus, we were able to elucidate mechanisms of inheritance bias. We find inheritance bias through homing in double heterozygous males, but find that a previous report of the same drive occurred through meiotic drive. We propose that other previously reported 'homing' design gene drives may in fact bias their inheritance through other mechanisms with important implications for gene drive design.

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Faculty Opinions recommendation of A synthetic homing endonuclease-based gene drive system in the human malaria mosquito.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.12355956.14701067 ◽

2011 ◽

Author(s):

George Dimopoulos

Keyword(s):

Homing Endonuclease ◽

Drive System ◽

Gene Drive ◽

Malaria Mosquito ◽

Human Malaria

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A Simulation on Relation between Power Distribution of Low-Frequency Field Potentials and Conducting Direction of Rhythm Generator Flowing through 3D Asymmetrical Brain Tissue

Symmetry ◽

10.3390/sym13050900 ◽

2021 ◽

Vol 13 (5) ◽

pp. 900

Author(s):

Hao Cheng ◽

Manling Ge ◽

Abdelkader Nasreddine Belkacem ◽

Xiaoxuan Fu ◽

Chong Xie ◽

...

Keyword(s):

Brain Tissue ◽

Power Distribution ◽

Low Frequency ◽

Field Potentials ◽

Spatial Spread ◽

Rhythm Generator ◽

Equivalent Dipole ◽

Head Surface ◽

Brain Rhythm ◽

Deep Brain

Although the power of low-frequency oscillatory field potentials (FP) has been extensively applied previously, few studies have investigated the influence of conducting direction of deep-brain rhythm generator on the power distribution of low-frequency oscillatory FPs on the head surface. To address this issue, a simulation was designed based on the principle of electroencephalogram (EEG) generation of equivalent dipole current in deep brain, where a single oscillatory dipole current represented the rhythm generator, the dipole moment for the rhythm generator’s conducting direction (which was orthogonal and rotating every 30 degrees and at pointing to or parallel to the frontal lobe surface) and the (an)isotropic conduction medium for the 3D (a)symmetrical brain tissue. Both the power above average (significant power value, SP value) and its space (SP area) of low-frequency oscillatory FPs were employed to respectively evaluate the strength and the space of the influence. The computation was conducted using the finite element method (FEM) and Hilbert transform. The finding was that either the SP value or the SP area could be reduced or extended, depending on the conducting direction of deep-brain rhythm generator flowing in the (an)isotropic medium, suggesting that the 3D (a)symmetrical brain tissue could decay or strengthen the spatial spread of a rhythm generator conducting in a different direction.

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