One Gene Might Have Lead to Modern Human Brain

By Alejandro Adrian LeMon, PhD News Editor on May 15, 2011

An international community of researchers from Turkey and Yale School of Medicine have discovered the mystery of human intelligence -- a minuscule difference within a single gene that determines the formation of the brain, according to a study published in this month�s Journal Genetics.

Researchers from Yale University found that the absence of two nucleotides within the gene laminin gamma3 (LAMC3) was seen in a patient whose brain lacks the characteristic folds in certain parts of the cerebral cortex. Nucleotides, or genetic letters, are the main building blocks of genes with over 3 billion in the human genetic alphabet.

Lead researcher Murat Gunel, author of the study and co-director of the Neurogenetics Program, and professor of genetics and neurobiology at Yale, Ph.D., says: "The demonstration of the fundamental role of this gene in human brain development affords us a step closer to solve the mystery of the crown jewel of creation, the cerebral cortex."

The human brain has a folded, ruffled appearance only seen in mammals with high intelligence, such as elephants and dolphins, and is most defined in humans. These convolutions aren't seen in mammals such as mice or other rodents.

These folds allow more surface area of the cerebral cortex and higher complex thought without the need for extra space. Despite the significance of these foldings, no research has been able to find out how the brain creates them.

The LAMC3 gene, previously thought to be involved in embryonic development, may be essential to the formation of these foldings.

A study on the gene shows that it is crucial in the the development of dendrites, which create connections between brain cells.

Gunel concluded: "Although the same gene is present in lower organisms with smooth brains such as mice, somehow over time, it has evolved to gain novel functions that are fundamental for human occipital cortex formation and its mutation leads to the loss of surface convolutions, a hallmark of the human brain."

The research study was funded by the National Institute of Neurological Disorders and Stroke through the Recovery Act. Several institutions from Turkey contributed to the study. Co-lead researchers were Tanyeri Barak and Kenneth Y Kwan of Yale.

Other Yale authors include Mehmet Bakırcıoğlu, Kaya Bilg�var, Richard A Bronen, Ahmet Okay �ağlayan, Murim Choi, Richard P Lifton, Angeliki Louvi, Shrikant Mane, Ali Kemal �zt�rk, Nenad �estan, Katsuhito Yasuno, Saliha Yılma, and Ying Zhu.

Source: Yale University via ScienceDaily