Question

why is there genetic variation? what processes shape the genetic structure of populations? what causes populations to be different? what causes divergence?

Answer 1

Q. why is there genetic variation? What processes shape the genetic structure of populations? What causes populations to be different? What causes divergence?

Q.why is there genetic variation-

Genetic variation- The variation in the DNA sequence in each of our genomes. Genetic variation makes us all unique and responsible for different hair color, skin colors the shape of faces. It cause by -

Gene flow - movement of genes from one population to another and is an important source of genetic variation. Also called gene migration, gene flow produces new genes into a population as organisms migrate into a new environment.

Mutations- changes in the DNA. A single mutation can have a large effect, but in many cases, evolutionary change is based on the accumulation of many mutations. Mutation is a change in the DNA sequence.

Sex- can introduce new gene combinations into a population. This is important source of genetic variation. Sexual reproduction promotes genetic variation by producing different gene combinations. Meiosis is the process by which sex cells or gametes are created. Genetic variation occurs as alleles in gametes are separated and randomly united upon fertilization.

Q.What processes shape the genetic structure of populations?

Genetic structure is pattern in the genetic makeup of individuals within a population. This change is due to four different processes mutation, selection-natural and artificial, gene flow, and genetic drift.

Q. what causes populations to be different?

Causes of different population are depending on different factors like high birth rate, low infant mortality, increased food production and improvement of public health. In the past, the death rate was high due to lack of food and poor health facilities. Natural increase is High birth rate in an area leads to high population growth. Good maternity services have helped to decrease mortality rate of kids younger than six. High production of food helps to reduce death that results from hunger and malnutrition. Improvement of health care facilities has been helpful in the control, diagnosis and treatment of different diseases.

Migration is the movement of organisms from one location to another. Migration when used in a population genetics the movement of individuals into or out of a defined population. If the migrating individuals stay and mate with the destination individuals, they can provide a sudden influx of alleles. After mating is established between the migrating and destination individuals, the migrating individuals will contribute gametes carrying alleles that can alter the existing proportion of alleles in the destination population.

Q. What causes divergence?

Answer: Genetic divergence is the process in which two or more populations of an ancestral species accumulate independent genetic changes-mutations after the populations have become reproductively isolated for some period of time.

The genetic divergence involves mutations and gives rise to significant morphological and physiological changes. Genetic divergence always accompany with reproductive isolation due to novel adaptations via selection, due to genetic drift. Molecular genetics level, genetic divergence is due to changes in a small number of genes in a species, resulting in speciation.

Divergence is a result of a significant, single, dominant mutation in a genetic locus. Divergence and reproductive isolation are the outcome of multiple small mutations over evolutionary time.