Genetic terminology, Biology

GENETIC TERMINOLOGY

(i)         Gene - Mendel used the term factor for a gene. A gene is the unit of DNA responsible for the appearance and inheritance of character.

(ii)         Allele - It refers to the alternative forms of a gene which control the same character and located at the same locus in the homologous chromosomes.

(iii)        Gene Locus - It is the region on chromosome representing a single gene. The alleles of a gene are present on the same gene locus on the chromosome.

(iv)        Heterozygous - The prefix hetro means 'different' and zygous means 'a pair'. The organism in which both the factors of a character are unlike is said to be heterozygous or hybrid. Such organisms do not breed true on self fertilization eg. Tt.

(v)         Homozygous - The prefix homo means 'the same' and zygous means 'a pair'.The organism in which both the factors of a character are similar is said to be homozygous or genetically pure for that character. It gives rise to offsprings having the same character on self breeding. e.g TT or tt.

(vi)        Dominant and Recessive - A heterozygote possesses two contrasting factors or alleles but only one of the two is able to express itself, while the other remains hidden. The factor which gains expression in F hybrid is known as dominant factor while its allele is unable to express itself in presence of the dominant factor is recessive factor.

(vii)        Genotype - It is the genetic constitution of an organism which determines the characters.

(viii)       Phenotype - It is the appearance of an individual.

or

Phenotype of an individual refers to the expressed or observable structural and functional traits produced by interaction of genes and environment.

Note :- The term Genotype and Phenotype were coined by Johanssen.

(ix)        Pureline - Generations of homozygous which produce offsprings of only one type i.e. they breed true for their phenotype and genotype.

(x)        Genome - Sum total of genes in the haploid set of chromosomes and inherited as unit from parents to offspring.

(xi)            Genepool - All the genotypes of all organisms in a population form the gene pool.

Posted Date: 10/10/2012 3:32:34 AM | Location : United States







Related Discussions:- Genetic terminology, Assignment Help, Ask Question on Genetic terminology, Get Answer, Expert's Help, Genetic terminology Discussions

Write discussion on Genetic terminology
Your posts are moderated
Related Questions
Q. What are fossil fuels? The Fossil fuels like coal, oil and gas, form when organic material is preserved from the complete action of decomposers, generally buried deep and un

What is the cell division during the first stage of the embryonic development called? How is this stage characterized? The cell division in the first stage of the embryonic de

Considering a pair of homologous chromosomes containing a gene having two different alleles how many different genotypes can the individual present? If a gene of the diploid sp

Explain Transition Period from Renaissance to Modern Period? The transition period from the Renaissance to the Modern period produced many notable workers and much literature.

After Purchasing The following points should be considered for after purchase facilities. Avail of any training the software engineer or vendor may provide, even if it

HIV (Human Immuno Deficiency Virus) Infection and AIDS (Acquired Immune Deficiency Syndrome)

How are the symmetry and the nervous system characterized in echinoderms? Adult echinoderms, with cnidarians, are the animals that present radial symmetry, i.e., their body str

Arrhythmias especially in presence of hypokalemia, lack of mortality benefit. However, their efficacy in reducing the symptoms of heart failure has been established. Digoxin should

PHYLUM  PLATYHELMINTHES Definition and Introduction Bilateral and protostominal  organ  grade eumetazoans  without  a body cavity ( acoelomates)  platyhelminthes means fl

Define Applications of Isolated Soybean Proteins in Meat products? The major application of ISP in connection with meat and related products is based on the use of texturized I