Monday, 2 April 2012

Using genome analysis to feed the hungry

Using genome analysis to feed the hungry
When you think lean meat, you think chicken breast. The consumption and demand for chicken meat in the past 4 decades has increased. From 1967 to 1992 there was a 500% increase in the output from poultry plants (Ollinger, MacDonald & Madison, 2000).

Structural change in U.S. Chicken and Turkey Slaughter       
           In 2011, over 730,000 chickens were slaughtered each month in America alone (United States Department of Agriculture 2012).

Current plants have systems which result in a chicken’s growth reaching required weight at 5-7weeks of age (Animals Australia n.d.). With the increase in demand for chicken meat at an affordable price, it has become priority for many poultry plants to develop new ways to produce chicken meat fast and affordable.

The current plant systems rely on the somewhat, blind selective breeding of chickens in the hope of achieving poultry which grows fat, fast and is ready to be slaughtered within 5-7 weeks. Want to know what the genes are that associate with fast growth and obesity (body weight) in order to produce the best, the fastest. Recent research in animal genetics in the last year has found, through genome analysis, the chicken genes believed to be associated with obesity and body weight.

The new advancement in genetics that may open up new opportunities

The 2011 study conducted by Twito et al, has found, through comparative genome analysis, that there are genes in chickens associated to increased body weight (BW) and percentage abdominal fat weight (%AFW).

The process used in the study conducted by Twito et al (2011), involved a few steps. First step was to compare the genome sequences of layers against broilers. They then analysed the 150 genes related to human obesity and searched for chicken orthologues in the DNA pools of layers and broilers.
Single nucleotide polymorphism (SNP), which is a process of searching for single base-pair variations in DNA was then used by aligning the sequences of pooled DNA (Reece et al. 2012). Differences in allele frequency of orthologous gene sequences were then noted and statistically analysed against %AFW and BW.

For a video detailing the description of SNP's and how they are useful follow this Youtube link. -

Twito, et al (2011) used the human obesity gene map to compare 150 human genes known to be associated with obesity, to chicken genes, in search of orthologues. They compare new DNA sequences against existing sequences and these 150 were narrowed down to 90. Using Polymerase chain reaction (PCR) to selectively amplify these gene sequences resulted in 53 gene sequences that were used for genotyping (Twito et al, 2011).
After further SNP and chi-square testing 6 out of the 53 gene sequences showed significant differences in the size of layer compared to broiler chickens. Further analysis showed significant evidence to support the association between BW and/or %AFW and the two chicken orthologous genes ADRB2 and MFGE8 (Twito et al, 2011).

For a video detailing the PCR process follow this Youtube link. -  

The advancing genetics research and use of techniques like SNP and PCR are opening up new opportunities in research and development in all industries. The results of this study provide a new opportunity in the production of chicken meat. The identification of the two genes associated with fatness provides a new way to look at selective breeding of broiler chickens and new ways for plants to meet consumer demand. Furthermore, the study opens up more opportunities for more research with other species in order to understand the genetics of the developing obesity in many animals.

MUSCLE v.s FAT - working towards leaner meat!

Chicken Horror Movie Image

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