Introduction to DNA and Genes
Each DNA molecule consists of two strands held together by base pairs. The human genome comprises 3.2 billion base pairs, which define individual genetic makeup. Identical twins have identical genes, whereas non-identical twins share only 50% of their genes, highlighting genes as key determinants of individuality.
Research on Gene Creation
In December 2024, two research groups investigated gene formation:
- The University of Nevada, Reno, published their study in Molecular Biology and Evolution.
- The Max Planck Institute for Evolutionary Biology, Plön, Germany, reported findings in Genome Biology and Evolution.
Genetic Structure and Inheritance
The human genetic setup includes 24 chromosomes, numbered 1 to 22 plus the sex chromosomes X and Y. Humans inherit one set of genome from each parent, resulting in two genome sets per individual. Identical twins originate from a single zygote, while non-identical twins come from two separate zygotes.
Gene Expression and Function
- A gene is a segment of DNA, typically a few thousand base pairs long.
- Gene expression involves transcribing DNA to messenger RNA (mRNA), which in turn synthesizes proteins.
- There are 20,000 protein-coding genes and an equal number for RNA that influences other gene expressions.
Gene Duplication and Mutation
Susumu Ohno's theory from 1970 suggested that new genes arise from gene duplication. The University of Nevada, Reno, addressed gene duplication by observing increased DNA methylation in duplicated genes, reducing protein over-expression's negative effects and promoting mutation for new functions.
Experiment on Random DNA Sequences
- Max Planck Institute researchers inserted random DNA sequences into human cells.
- Resulting proteins were random, and after 20 days, cell type abundance varied, indicating random sequences could influence evolution.
Significance of Blood Groups
Blood groups (A, B, AB, O) are determined by variants of the ABO gene. Despite their apparent non-essentiality, all variants have been retained through evolution in humans and primates, showcasing evolutionary complexity.
