Related Experiment Video
Updated: Jul 17, 2026
04:59
Single Nucleotide Polymorphism-sensitive FISH Detection of Locus-specific Ribosomal RNA Transcription in Drosophila melanogaster
Published on: March 28, 2025
On the time for gene silencing at duplicate Loci
1Department of Mathematics, Monash University, Clayton, Victoria, Australia 3168.
Genetics
|November 1, 1983
Summary
A new formula estimates the time for mutant genes to fix at duplicate gene loci. This process, driven by mutation but slowed by selection, is modeled using diffusion approximations.
Area of Science:
- Population genetics
- Mathematical biology
- Evolutionary genetics
Background:
- Understanding gene fixation dynamics is crucial in evolutionary biology.
- Duplicate loci present unique challenges in modeling allele frequency changes.
- Previous studies have used numerical simulations to investigate these dynamics.
Purpose of the Study:
- To derive a simple approximate formula for the mean fixation time of mutant genes at two duplicate loci.
- To model the evolution of mutant allele frequencies using a two-dimensional diffusion process.
- To compare analytical results with existing numerical simulations and present new simulation data.
Main Methods:
- Development of an approximate analytical formula for fixation time.
- Transformation of a two-dimensional diffusion model into two univariate diffusions with different time scales.
- Comparison of analytical predictions with previous numerical studies and new simulations.
Main Results:
- A simple approximate formula for mean fixation time at duplicate loci was derived.
- Analytical results largely agreed with previous numerical studies.
- New simulation results supported the analytical findings, questioning some prior simulations.
Conclusions:
- The derived formula provides a valuable tool for estimating mutant gene fixation times.
- The diffusion model and its transformation offer insights into the evolutionary dynamics at duplicate loci.
- Discrepancies with some previous simulations highlight the importance of robust validation in computational evolutionary genetics.
Related Concept Videos
02:37Gene Duplication and Divergence
The seminal work of Ohno in 1970 popularized the idea of gene duplication and divergence. DNA sequence comparison studies reveal that a large portion of the genes in bacteria, archaebacteria, and eukaryotes was generated by gene duplication and divergence, indicating its critical role in evolution.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
02:05Duplication of Chromatin Structure
The process of chromosome duplication during cell division requires genome-wide disruption and re-assembly of chromatin. The chromatin structure must be accurately inherited, reassembled, and maintained in the daughter cells to ensure lineage propagation.
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
01:52Eukaryotic Transcription Inhibitors
Certain biochemical processes, such as embryonic development and cell growth regulation, depend on the repression of specific genes. DNA binding proteins known as eukaryotic transcription inhibitors regulate the repression of gene expression in eukaryotes. The presence of these inhibitors at the required location and time in the cell is triggered by the presence of hormones and additional signals from other cells.
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
02:50Dosage Compensation
In animals, gender is determined by the number and type of sex chromosome. For example, human females have two X chromosomes, and males have one X and one Y chromosome, whereas C.elegans with one X chromosome is a male, and the one with two X chromosomes is a hermaphrodite.
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
02:30Genomic Imprinting and Inheritance
Diploid organisms inherit genetic material through chromosomes from both parents. Copies of the same gene are known as alleles. In most cases, both alleles are simultaneously expressed and allow various cellular processes to function optimally. If one of the alleles is missing or mutated, the expression of the other allele can compensate; however, this is not true for all genes.
The expression of some genes depends on which parent passed the gene to the offspring, through a phenomenon known as...
The expression of some genes depends on which parent passed the gene to the offspring, through a phenomenon known as...
02:02Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...