Genome, Chromosomes and Genes27 June 2012
GLOBAL - The blueprint of the next generation is stored in DNA grouped into genes and organised in chromosomes. The chromosomes are present in the nucleus of every cell in an animal's body and control the way each cell works. These chromosomes make up the animal's genome. Now we have the chicken genome mapped, it is possible to start marking genes and identifying their role in the traits we are interested in.
The process of identifying which genes affect which traits is long and expensive but Hendrix Genetics have invested heavily and are leading the way. Once we can identify key genes, the next generation can be screened at an early age and the accuracy and speed of genetic progress improved. Traditional breeding continues alongside this new technology which it is already bringing benefits.
Breeding goals are defined after consultation between the geneticists and commercial departments agree market trends. For ISA, the layer breeding division of Hendrix Genetics, the most important goal for the worldwide market is feed conversion to saleable eggs.
Today traits such as early maturity and feed intake are considered to be optimal, so the selection pressure focuses on other traits , such as laying persistency, shell quality and robustness/liveability. Concentrating on these traits brings benefits other than the obvious. Getting more for less means less pollution, a lower carbon footprint and efficient production of important animal protein for an ever growing world population. Selection pressure on liveability and robustness helps feed conversion but also ensures robust reliable animals that can produce well in different housing systems and under different levels of management.
Improvements generation by generation
The animals in Hendrix Genetics program breed through normal sexual reproduction where semen on known males is used to fertilise hens using artificial insemination techniques. The benefit of sexual reproduction is that this produces genetic variation and therefore measurable differences between the offspring of a particular hen and cockerel. Reliability and continuing improvement are fundamental to keeping egg producers supplied with the right genetics to survive in today's competitive food industry. To choose the best animals for the next generation requires a balanced approach across a wide range of measured traits. This includes not only the elite animals on the pure line farms but also the performance of their offspring on field test farms.
Measure, collect and conclude
The breeding program of ISA consists of individual pure line breeding and pedigreed crossbred daughter group field testing (Recurrent Tests). Based on well described breeding goals the best individuals of the pure lines are selected. The pure line R&D farms and the field test farms generate performance data that are collected and stored at ultra modern database systems. The stored data are the basis for the determination of the breeding values. For this breeding value estimation BLUP (Best Linear Unbiased Prediction) technology is being used.
First success: breeding out "fishy taint" from eggs
Some brown egg layers have a faulty gene that means they are unable to digest rape meal without leaving a fishy taint to the eggs they lay. Hendrix Genetics successfully patented the genomic screening process for identifying the carriers of this gene and hence were the first company to successfully remove it from their lines. This means clients of the ISA breeds have been able to use rape meal for the last 3 years, saving feed costs without risk of consumer complaint.
Some traits, such as egg size, are easy to measure and adjust generation after generation. They have what geneticists call a high inheritability. Other traits, such as liveability and docility, are much more difficult to select for using traditional breeding. Identifying the genes that affect these characteristics would represent a highly significant step forward. For example, is there a common pattern of genes to hen susceptible to E. Coli peritonitis, a common cause of death in layers. Hendrix Genetics are committed to using genomics to provide better breeding today for a brighter life tomorrow.
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