First Human clock gene was discovered by:

Question

Accepted Answer

The correct option is 3: Ying-Hui-fu

Dr. Ying-Hui Fu, alongside her colleague Dr. Louis Ptáček and their research group at the University of Utah, is correctly credited with the landmark discovery of the first gene mutation directly linked to a human circadian rhythm disorder. In a pivotal 1999 study, they identified a single point mutation in the human *Period 2* (*hPer2*) gene as the cause of an inherited condition known as Familial Advanced Sleep Phase Syndrome (FASPS). This syndrome is characterized by an intrinsic acceleration of the biological clock, causing affected individuals to naturally fall asleep and wake up significantly earlier than the general population. This discovery was transformative because it functionally proved that the molecular clock mechanism, previously understood from animal models, was operational and genetically controlled in humans. The specific mutation Fu’s team found in *hPer2* affects a key site for phosphorylation, which in turn shortens the period of the molecular feedback loop that governs the human sleep-wake cycle.

The incorrect option is 1: Rono Konopka

Rono Konopka is a monumental figure in chronobiology, but his discovery was of the very first clock gene ever found, not the first *human* one. Working with Seymour Benzer in the early 1970s, Konopka conducted meticulous genetic screening in the fruit fly, *Drosophila melanogaster*, which led to the identification of the *period* (*per*) gene. This gene provided the first molecular evidence that biological rhythms were governed by genetic factors, demonstrating that mutations could lengthen, shorten, or abolish the organism's 24-hour cycle. This foundational research established the conceptual and molecular basis for the entire field of chronobiology, but it concerned the insect clock.

The incorrect option is 2: Seymour

The inclusion of 'Seymour' in the options most likely refers to Seymour Benzer, the highly respected geneticist and neurobiologist. Benzer was the research supervisor and co-author on the seminal 1971 publication with Rono Konopka that first described the *period* gene in *Drosophila*. While Benzer's mentorship and collaborative role were crucial to this initial breakthrough in clock genetics, his primary contribution was to the discovery in the fruit fly, not the later, specific identification of the functional *human* clock gene, *hPer2*, which was the work of Dr. Fu's laboratory. His focus was on establishing the genetic control of rhythmicity in a model organism.

The incorrect option is 4: Hee Supshia

Hee Supshia is a name that does not appear in the primary historical accounts associated with the key discoveries of the core human circadian clock genes. The major components of the human molecular clock—including the *Period* genes, *Cryptochrome* genes, and the *CLOCK-BMAL1* complex—were identified, mapped, and functionally analyzed by a few specific research groups worldwide during the 1990s and early 2000s. The field of molecular chronobiology is well-documented, and this name is not recognized as a principal investigator responsible for the initial cloning or functional characterization of the first human clock gene. The discovery of the first human gene functionally linked to rhythmicity belongs squarely to the team that identified the FASPS mutation.