What is the difference between genes and traits

The specific characteristics of individual determined by the genes are called traits. However, certain traits are determined by environmental condition or both inherited genes and environmental factors.

Some traits are passed on from parents to offspring, and these types of traits are referred to as inherited traits. A single gene determines several traits and certain traits are determined by few genes.

Some traits are observable ex: hair color, skin color, eye color, etc. Observable traits also are called phenotypic traits. The process of turning coded genetic information into a protein involves transcription and translation. When transcription is initiated, part of the DNA double helix opens and unwinds. The mRNA separates from the DNA, leaves the nucleus, and travels into the cell cytoplasm the part of the cell outside the nucleus—Home.

Inside a Cell Inside a Cell Often thought of as the smallest unit of a living organism, a cell is made up of many even smaller parts, each with its own function. Human cells vary in size, but all are quite small. There, the mRNA attaches to a ribosome, which is a tiny structure in the cell where protein synthesis occurs. Each molecule of tRNA brings one amino acid to be incorporated into the growing chain of protein, which is folded into a complex three-dimensional structure under the influence of nearby molecules called chaperone molecules.

These cells look and act differently and produce very different chemical substances. However, every cell is the descendant of a single fertilized egg cell and as such contains essentially the same DNA. Cells acquire their very different appearances and functions because different genes are expressed in different cells and at different times in the same cell.

The information about when a gene should be expressed is also coded in the DNA. Gene expression depends on the type of tissue, the age of the person, the presence of specific chemical signals, and numerous other factors and mechanisms. Knowledge of these other factors and mechanisms that control gene expression is growing rapidly, but many of these factors and mechanisms are still poorly understood. The mechanisms by which genes control each other are very complicated.

Genes have chemical markers to indicate where transcription should begin and end. Various chemical substances such as histones in and around the DNA block or permit transcription. Cells reproduce by dividing in two. Because each new cell requires a complete set of DNA molecules, the DNA molecules in the original cell must reproduce replicate themselves during cell division.

Replication happens in a manner similar to transcription, except that the entire double-strand DNA molecule unwinds and splits in two. After splitting, bases on each strand bind to complementary bases A with T, and G with C floating nearby.

When this process is complete, two identical double-strand DNA molecules exist. There are also chemical mechanisms to repair DNA that was not copied properly. However, because of the billions of base pairs involved in, and the complexity of, the protein synthesis process, mistakes may happen. Such mistakes may occur for numerous reasons including exposure to radiation, drugs, or viruses or for no apparent reason.

Minor variations in DNA are very common and occur in most people. Most variations do not affect subsequent copies of the gene.

Mistakes that are duplicated in subsequent copies are called mutations. Inherited mutations are those that may be passed on to offspring. Mutations can be inherited only when they affect the reproductive cells sperm or egg. Mutations that do not affect reproductive cells affect the descendants of the mutated cell for example, becoming a cancer but are not passed on to offspring.

Mutations may be unique to an individual or family, and most harmful mutations are rare. Mutations may involve small or large segments of DNA. Depending on its size and location, the mutation may have no apparent effect or it may alter the amino acid sequence in a protein or decrease the amount of protein produced. If the protein has a different amino acid sequence, it may function differently or not at all. An absent or nonfunctioning protein is often harmful or fatal. For example, in phenylketonuria Phenylketonuria PKU Phenylketonuria is a disorder of amino acid metabolism that occurs in infants born without the ability to normally break down an amino acid called phenylalanine.

Phenylalanine, which is toxic This deficiency allows the amino acid phenylalanine absorbed from the diet to accumulate in the body, ultimately causing severe intellectual disability. In rare cases, a mutation introduces a change that is advantageous. For example, in the case of the sickle cell gene, when a person inherits two copies of the abnormal gene, the person will develop sickle cell disease Sickle Cell Disease Sickle cell disease is an inherited genetic abnormality of hemoglobin the oxygen-carrying protein found in red blood cells characterized by sickle crescent -shaped red blood cells and chronic However, when a person inherits only one copy of the sickle cell gene called a carrier , the person develops some protection against malaria Malaria Malaria is infection of red blood cells with one of five species of Plasmodium, a protozoan.

Malaria causes fever, chills, sweating, a general feeling of illness malaise , and sometimes diarrhea Although the protection against malaria can help a carrier survive, sickle cell disease in a person who has two copies of the gene causes symptoms and complications that may shorten life span.

Natural selection refers to the concept that mutations that impair survival in a given environment are less likely to be passed on to offspring and thus become less common in the population , whereas mutations that improve survival progressively become more common. Thus, beneficial mutations, although initially rare, eventually become common. The slow changes that occur over time caused by mutations and natural selection in an interbreeding population collectively are called evolution.

Not all gene abnormalities are harmful. For example, the gene that causes sickle cell disease also provides protection against malaria. A chromosome is made of a very long strand of DNA and contains many genes Genes Genes are segments of deoxyribonucleic acid DNA that contain the code for a specific protein that functions in one or more types of cells in the body. The genes on each chromosome are arranged in a particular sequence, and each gene has a particular location on the chromosome called its locus.

In addition to DNA, chromosomes contain other chemical components that influence gene function. Except for certain cells for example, sperm and egg cells or red blood cells , the nucleus of every normal human cell contains 23 pairs of chromosomes, for a total of 46 chromosomes.

Normally, each pair consists of one chromosome from the mother and one from the father. There are 22 pairs of nonsex autosomal chromosomes and one pair of sex chromosomes. Paired nonsex chromosomes are, for practical purposes, identical in size, shape, and position and number of genes. Because each member of a pair of nonsex chromosomes contains one of each corresponding gene, there is in a sense a backup for the genes on those chromosomes.

The pair of sex chromosomes determines whether a fetus becomes male or female. Males have one X and one Y chromosome. Females have two X chromosomes, one from the mother and one from the father. Recessive traits can only be expressed if the genotype is homozygous. For example, a V-shaped hairline is a dominant trait, while a straight hairline is recessive. In order to have a straight hairline, both hairline alleles need to be straight hairlines. However, in order to have a V-shaped hairline, only one of the two hairline alleles need to be V-shaped.

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She currently writes for Nature Middle East, the regional publication of Nature. Updated January 06, An allele is a specific form of a gene. Function Genes are responsible for the expression of traits. Alleles are responsible for the variations in which a given trait can be expressed.