Why Do Some Finches Have Large Beaks While Others Have Small Ones?

Cameroonian finches have always had either a large beak size, or smaller beaks.  This had always been thought to be due to a difference in how hard the seeds they eat, much like the theory of Darwin's finches.  However, birder and biologist Tom Smith, investigated this further by establishing a breeding colony of these finches.  Based on the results, the trait seemed to be due to Mendelian genetics, and the larger beak was the dominant trait, with a 3:1 ratio of large to small beaks.  This was the stepping stone to figuring out which genes affected this trait, and with the help of Bridgett vonHoldt, Princeton biologist, the question was solved.  She found a stretch of DNA with 300,000 base pairs that always seemed to vary between the large and small-beaked finches, with the gene IFG-1 in the center.  This gene is a growth-factor gene. vonHoldt said that this is a gene she has studied in canines as well and that if it is changed how it is expressed, a normal-sized dog could be changed into a dwarf-sized dog.  This being said, not only can he gene affect the whole animal, but a specific trait as well, which is present in the case of the finches and their beak size.  This all depends on where the gene is located on the genome and where it gets expressed, says vonHoldt.
https://www.sciencedaily.com/releases/2018/11/181119064118.htm
https://www.princeton.edu/news/2018/11/19/princeton-geneticist-solves-long-standing-finch-beak-mystery

Pair of Genes Responsible for Wing-Shaped Fin Development in Batoids

Researchers at the University of Chicago have identified a pair of genes responsible for the wing shaped fins of skates and rays.  Rays, skates and other batoids have some of the most unique fin shapes of all aquatic species.  In an attempt to further understand how limbs in all animals develop researchers at the university of Chicago investigated the genetic and molecular cause of the unique shape of fins found in batoids.  The team accomplished this by studying gene expression in the embryos of batoids. In the developing limb, there are genes and growth factors arranged in a specific order which help to create the apical ectodermal ridge (AER).  The AER is a region that stimulates cell proliferation along the growing edge of the limb which is responsible for elongation and proper development.  They discovered that early in development batoids mirror limb development of other fish and tetrapod species. However unlike other fish and tetrapods which only have one AER, the batoids posses a second AER.  The presence of this second AER allows for development of the pectoral fin towards the tail and the head of the ray.

The researchers also found that different groups of genes control the two different regions of the fin.  The 5' Hox family of transcription factors and the Fgf10 growth factor are commonly found among fish species was also found and active in the batoids, this group of genes was responsible for growth towards the tail.  The region growing towards the head was controlled by 3' Hox transcription factors and the Fgf7 growth factor.  In species other than the batoids, the 3' Hox and Fgf7 are found at the base of the growing limb, the presence of these genes in the anterior portion of the growing pectoral fin of batoids suggests that this is a unique adaptation of the batoid species and is responsible for the second AER, giving them their fin shape.

Interestingly, although the two regions of the rays fin are nearly identically the gene expression in these regions is totally different.  This group of species have different mechanisms that control fin development compared to other fish species giving them their unique fin shape.

Gene Therapy is just a drop away

Philip K. Liu, Ph.D., of the Martinos Center for Biomedical Imaging at Harvard Medical School, and his collaborators, Drs. H. Prentice and J. Wu of Florida Atlantic University have developed a technique which quickly delivers and monitors gene therapy for brain disorders. The doctors used a simplified technique of eye drops to deliver the granulocyte colony stimulating factor  into a mouse model of brain ischemia. Brain ischemia is a condition where there is insufficient blood flow to the brain.

            The  G-CSF was transported by inserting the gene into an adenovirus. The adenovirus was then administered through eye drops. The scientists concluded the growth factor treatment led to a reduction in brain atrophy, neurological defects, and the death in the mice. After the growth factor drops were added to the mice, MRI was used to monitor the success. The overall combination of non-invasive, simple delivery has the potential to improve experimental gene therapy in animal models.

The primary target for Dr. Liu and his team was to develop a simple technique that administers the G-CSF quickly to the brain without the accompaniment of highly trained staff and elaborate technologies. This expeditious process could be the difference in saving a stroke or cardiac arrest patient’s life. The second target for Dr. Liu was to include a noninvasive procedure that delivers G-CSF to the brain expressed at therapeutic levels. The target is to administer the system to animals then translate over to humans.   

This simple technique could lead to the improvement of stroke, Alzheimer’s dementia, Parkinson’s disorder and ALS.  

Although the test results in human trials were unsuccessful, I believe this gene therapy study is quite beneficial to the study of human health. This experiment could lead to the potentially life saving growth factor in critical patients. Because this process is noninvasive, it is also a lot less stressful on people with an illness.

New Genes Found that Determine Height in Individuals

Our heights are strongly related to the genes we inherited from our parents. Studies suggested that about 80 percent of the variance in height among people is closely lined to their DNA.

The largest genetic study of height-related genes to date titled the Genetic Investigation of Anthropometric Traits (GIANT). It has been identified that 423 genetic regions connected to height. This data provided explanation that about 60% of the genetic component plays a large role in determining a person height. Dr. Joel Hirschhorn, leader of the GIANT consortium at Boston Children’s Hospital argues, “Trait like height, which isn’t determined by a single gene but likely the combined effects of multiple genes involved in multiple different processes from bone growth to cell growth.”

The most recent analysis published in the journal “Nature Genetics,” describes the gene variants commonly shared among individuals (not mutation) that likely play a large role in people heights. Researchers obtained more than 250,000 genomes from people of various heights and correlated their stature with the genetics. It was found that many similar factors related to height such as skeletal growth and collagen. Mutated skeletal growth and collagen in certain individuals cause medically short stature.

Researchers found that previous gene regions related to height involved in cell growth but no in skeletal functions. New research focuses on the regions of interest and to isolate specific genes and the proteins. These proteins include growth factors, enzymes, and other agents that are responsible for determining height. If successful, new treatment may arise to treat medical conditions of short stature or gigantism.

Article: http://time.com/3462490/new-genes-found-that-determine-your-height/