Summary: Researchers have discovered two genes from the “dark matter” of the human genome that have an impact on head size and neural signaling. The team examined how these duplicated genes might relate to what makes the human mind special using the entire human genome and fish versions.
Additionally, the findings provide a blueprint for further research into hundreds of genes that might reveal information about dementia, speech disorders, and brain development. This research opens up new strategies for understanding how human consciousness was formed genetically.
Important Information
- Dark Matter Genes: Reproduced genes in difficult-to-sequence DNA parts influence head characteristics.
- New revelations: GPR89B and FRMPD2B are linked to neural sensing and brain size.
- Broader Impact: Research into speech disorders and autism may be aided by these insight.
Origin: UC Davis
What distinguishes the human mind from other species?
A brand-new study, which was published on July 21 in the journal Cell, discovers two genes that are related to features in the human mind.
The study may reveal more about how the human mind functions and how it evolved, as well as where vocabulary problems and autism come from.
The newly identified genes are found in parts of the “dark problem” of the human genome, which are areas of DNA that have a lot of duplicated or follow patterns, making them challenging to experiment until lately.
Reconstructing a DNA collection from repeat sequences would be like trying to match websites using single words like “and” and” the” if assembling a collection is like putting up a book from torn-up sites. There are many opportunities for overlap and mismatches.
Although challenging to study, DNA repeats are also thought to be crucial for evolution because they can produce fresh translations of existing genes for selection to apply.
This has historically been a very challenging issue. Megan Dennis, senior author and associate professor in the Department of Biochemistry and Molecular Medicine and the MIND Institute at the University of California, Davis, said that “people don’t know where to start.”
Dennis was a coauthor in 2022 on a paper describing the first complete sequence of a human genome, known as the “telomere to telomere” reference genome. The challenging areas that were left out of the original draft, which was used to make fresh discoveries, are now included in this reference.
Identifying genes in the human brain
To find duplicate genes, Dennis and colleagues used the telomere-to-telomere human genome. Then, they sorted those genes for genes that are conserved, based on sequences from the 1000 Genomes Project, and expressed in the brain, found in all humans.
About 250 candidate gene families were released. They selected some of them for use in a zebrafish animal model for research. At least two of these genes may have contributed to features of the human brain: one that called GPR89B led to slightly larger brains, and another, FRMPD2B, caused alterations in synapse signaling.
It’s pretty cool to think that a human brain trait can be tested with fish, Dennis said.
According to Dennis, the dataset in the , Cell , paper is meant to be a resource for the scientific community. It should make it simpler to find mutations in duplicated regions, such as those found in autism or language deficits, that were missed in earlier genome-wide screening.
Dennis said,” It opens up new areas.”
Daniela Soto, José , Uribe-Salazar, Gulhan Kaya, Ricardo Valdarrago, Aarthi Sekar, Nicholas Haghani, Keiko Hino, Gabriana La, Natasha Ann Mariano, Cole Ingamells, Aidan Baraban, Zoeb Jamal, Sergi Simó , and Gerald Quon, all of whom are currently enrolled at UC Davis, Tychele Turner, Washington
Funding: The work received in part funding from grants from The Wellcome Trust, The National Science Foundation, and the National Institutes of Health.
About this news about neuroscience and genetics
Author: Andrew Fell
Source: UC Davis
Contact: Andrew Fell – UC Davis
Image: The image is credited to Neuroscience News
Open access to original research.
” The expansion of human-specific gene expression contributes to brain evolution.,” writes Megan Dennis and others. Cellulose
Abstract
The expansion of human-specific gene expression contributes to brain evolution.
Although duplicating genes from the human lineage likely contributed to brain evolution, problems are still present in their discovery as a result of sequence-assembly errors.
We identified 213 human-specific gene families using a complete telomere-to-telomere genome sequence.
362 paralogs were identified from these in all modern human genomes and brain transcriptomes, making them the best candidates for human-universal brain features.
Long-read DNA sequencing of hundreds of modern humans revealed previously undiscovered patterns of selection, including for the T cell marker , CD8B.
We created zebrafish CRISPR “knockout” models of nine orthologs and inserted mRNA-encoding paralogs, effectively “humanizing” larvae, to understand roles in brain development.
Our findings point to two genes that are involved in the development of signature characteristics of the human brain:  , GPR89B , in dosage-mediated brain expansion, and  , FRMPD2B , in altered synapse signaling.
Our holistic approach provides insights and a comprehensive resource for studying the factors driving human brain evolution in terms of gene expansion.
