DNA- An Introduction

Deoxyribonucleic acid, more commonly known as DNA, is a complex molecule that contains all of the information necessary to build and maintain an organism. All living things have DNA within their cells. In fact, nearly every cell in a multicellular organism possesses the full set of DNA required for that organism.

However, DNA does more than specify the structure and function of living things — it also serves as the primary unit of heredity in organisms of all types. In other words, whenever organisms reproduce, a portion of their DNA is passed along to their offspring. This transmission of all or part of an organism's DNA helps ensure a certain level of continuity from one generation to the next, while still allowing for slight changes that contribute to the diversity of life.

Source of info.

1. http://www.nature.com/scitable/topicpage/introduction-what-is-dna-6579978

2. https://ghr.nlm.nih.gov/primer/basics/chromosome

Comments

Natural Selection

Natural selection is one of the basic mechanisms of evolution, along with mutation, migration, and genetic drift ( Berkeley ) It is a process in nature in which organisms possessing certain genotypic characteristics that make them better adjusted to an environment tend to survive, reproduce, increase in number or frequency , and therefore, are able to transmit and perpetuate their essential genotypic qualities to succeeding generations . This theory was put forward by Charles Darwin, trying to explain how evolution of species occurs . Look at an example to help make the concept natural selection clearer: Industrial melanism is a phenomenon that affected over 70 species of moths in England. It has been best studied in the peppered moth, Biston betularia . Prior to 1800, the typical moth of the species had a light pattern. Dark colored or melanic moths were rare and were therefore c...

Chromosomes and Genes: An Introduction

Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. Chromosome is composed of DNA coiled and condensed around nuclear proteins called histones. Humans inherit one set of chromosomes from their mother and a second set from their father. In total, most human cells contain 46 chromosomes with 22 pairs of autosomes, or non-sex chromosomes, and two sex-determining chromosomes. The sex chromosomes in humans are called X and Y. Females carry two X chromosomes, while males carry one X and one Y chromosome. Cells of the body that contain two sets of chromosomes are called diploid. Gene: It is a linear sequence /segment of DNA that provides the coded instructions for synthesis of RNA, which, when translated into protein, leads to the expression of hereditary character. ...

Genetics for beginners

Search This Blog