Sequencing the Genome of Chickens

Two silkie chickens, sometimes called "black boned chicken" in China

A recent study by Feng Zhu, Zhong-Tao Yin, Qiang-Sen Zhao, Yun-Xiao Sun, Yu-Chen Jie was set out to sequence the genes of metabolic, reproductive and immunity of silkie chickens and provide it to the public. The research aimed to discover more of the genetic makeup of chickens, specifically the silkie breed by comparing the genetic sequences of 8 males and 7 females. This would help determine hidden or unknown genes within chickens, that could be potentially be observed in other breeds. After obtaining the genetic sequence of the silkie chickens, it was compared to the publicly available genomes of other chicken breeds. The researchers had noticed more than 285 protein-coding genes in the silkie chickens that had not been discovered. The researched have now refuted the assumption of small genetic mutation for certain traits due to the large genomic structure and genetic variation. The results also contradict the previous belief that the silkie chickens do not have a protein-coding gene that improves its immunity to certain diseases.

I find it very interesting how much information can be discovered by obtaining the genetic sequences of an animal. It could have been possible that the 285 protein-coding genes would never have been observed without the genetic sequence. The sequence also helps give a more definitive answer instead of relying on an assumption, such as the assumption that the chickens lacked a gene to help immunity with certain diseases. The genetic sequences could be used to further improve egg and poultry production, and to help keep chickens healthier. 

Sources:

Nature

National Library of Medicine

 

MicroRNAs Can Improve Gene Expression

 MicroRNAs are a class of non-coding RNAs that play an important role in controlling gene expression. That is, they help cells control the types and amounts of protein they make. MiRNA mainly controls gene expression by binding with messenger RNA(mRNA) in the cell cytoplasm. Instead of immediately translating, the marked mRNA will either be destroyed or have its components recycled, or preserved and translated later. In addition, if the level of a specific miRNA is underexpressed in the cell, the protein that is normally regulated will be overexpressed in the cell. In so, they are inversely proportional.  

A recent research study aimed to better characterize miRNAs involved in glycosylation by probing the miRNA of two glycosylation proteins: ST6GAL 1 and ST6GAL 2. It was previously found that ST6GAL 1 is overactive in pancreatic cancer, interspersing cancerous cells' membranes with 2,6-sialic acid. To determine how miRNAs adjust enzyme expression, a sensor was developed using a gene's regulatory region(where miRNA binding occurs) and a sequence coding for a fluorescent protein. The sensor was expressed in dividing cells. If miRNAs inhibited a protein's translation, the cells' color dims, while if it turned up gene expression, the cells glow brighter. It was discovered that the miRNAs that interact with ST6GAL 2 downregulate its expression, while those that interacted with ST6GAL 1 increased its expression, also increasing levels of 2,6-sialic acid. Mutating potential miRNA binding sites caused upregulation to disappear, proposing that miRNAs directly control gene expression.

This discovery is a major innovation in cancer research. This is because abnormally low levels of miRNA can lead to overexpression in genes that miRNA regulates, leading to cancer development. The correction of these specific miRNAs can normalize the gene regulatory network and signaling pathways, and reverse the phenotype in cancerous cells. 

Puma Inbreeding

Pumas can be found all over the United States, as well as South America. Recently the entire genome has been sequenced revealing that the species is highly inbred. Starting in South America, pumas migrated to North America about 300,000 years ago. With analysis of their DNA, there were markers for inbreeding that is most likely to be caused by the wide area these animals are found, coupled with decreasing land to live with human interference. As the land shrunk, populations grew smaller and more sparred, and more isolated leaving the cats to reproduce with a limited gene pool. With this news scientists have tried to diversify the populations by moving individuals into other groups of pumas, but this has unfortunately not shown much improvement.



https://www.the-scientist.com/image-of-the-day/image-of-the-day--puma-genome-sequencing-66604
related link: https://www.google.com/amp/s/phys.org/news/2019-10-genome-sequencing-pumas-inbreeding.amp