Prof. Romziah Sidik, Ph.D. drh.

2010

RefferencesAn Introduction to Genetic Analysis, 7th

editionAnthony JF Griffiths,1 Jeffrey H Miller,2

David T Suzuki,1 Richard C Lewontin,3 and William M Gelbart3

1University of British Columbia2University of California, Los Angeles3Harvard UniversityNew York: W. H. Freeman; 2000.ISBN: 0-7167-3520-2

Refferenceshttp://upload.wikimedia.org/wikipedia/

commons/0/07/Gene.png

GENEDefinition: A gene is a unit of heredity in a living

organism. Gene normally resides on a stretch of DNA that

codes for a type of protein or for an RNA chain which it has a function in the organism.

All living organisms depend on genes, as they specify all proteins and functional RNA chains.

Genes hold the information to build and maintain an organism's cells and pass genetic traits to offspring, although some organelles (e.g. mitochondria) are self-replicating and are not coded for by the organism's DNA.

This stylistic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). The chromosome is X-shaped because it is dividing. Introns are regions often found in eukaryote genes that are removed in the splicing process (after the DNA is transcribed into RNA): Only the exons encode the protein. This diagram labels a region of only 50 or so bases as a gene. In reality, most genes are hundreds of times larger.

The chemical structure of a four-base fragment of a DNA double helix.

RNA GENES & GENOME

When proteins are manufactured, the gene is first copied into RNA as an intermediate product. In other cases, the RNA molecules are the actual functional products. For example, RNAs known as ribozymes are capable of enzymatic function, and microRNA has a regulatory role. The DNA sequences from which such RNAs are transcribed are known as RNA genes.

CHROMOSOMEChromosomes is a total complement of genes in an organism or

cell is known as its genome

Genome may be stored on one or more chromosomesThe region of the chromosome at which a particular

gene is located is called its locus. A chromosome consists of a single, very long DNA helix

on which thousands of genes are encoded. Prokaryotes—bacteria and archaea— are typically store

their genomes on a single large, circular chromosome sometimes supplemented by additional small circles of

DNA called plasmids, which usually encode only a few genes and are easily transferable between individuals

CHROMOSOME NUMBEROne cell of cattle include: 30 pair of chromosome (homolog), pig : 20 pair., sheep: 27 pair, goat: 30 pair poultry) : 39 pair

Basic Term in Animal Breeding F1 generation :Offspring (fillial) by crossing homozygot F2 generation : by crossing among F1Genotype :Constitution of gene for specific character Heterozygot :Difference Allele become difference one

chaeracter (Yy), Aa, AaBbCcHomozygot : Both have the same allele for one character

Hybrid : heterozygot on fillial by crossing between

mono zygote animal (pure breed).Un complete Domination (Incomplete dominance)

Gen and Chromosom

Pair of Genes, then it free split and together again on zygote

Principle of Animal Breeding

According to the theory of Mendelian inheritance, variations in phenotype—the observable physical and behavioral characteristics of an organism—are due to variations in genotype, or the organism's particular set of genes, each of which specifies a particular trait. Different forms of a gene, which may give rise to different phenotypes, are known as alleles.

MUTATIONMutations propagated to the next generation lead

to variations within a species' population. Variants of a single gene are known as alleles,

and differences in alleles may give rise to differences in traits.

Although it is rare for the variants in a single gene to have clearly distinguishable phenotypic effects, certain well-defined traits are in fact controlled by single genetic loci.

A gene's most common allele is called the wild type allele, and rare alleles are called mutants. However, this does not imply that the wild-type allele is the ancestor from which the mutants are descended.