Question

Explain how chromosomal inheritance generates genetic variation in sexual reproduction.( Please use the terms below in your answer)

segregation

Independent assortment

Population genetics

Chromosomal basis of inheritance

Mutated allele

Nondisjunction

transposition

Answer 1

Genetic variation can be defined as the make up of organisms wthin a population change .Genes are inherited segments of DNA that contains codes for the production of proteins .Genes exists in alternate versions or alleles that can determine distinct traits that can be passed on from parents to offsprings.The genetic variations that rise in a population happen bychance ,but the process of natural selection does not .Natural selection is the result of the interactions between genetic variations in a population and the environment.The environment determines which genetic variations are more favorable or better suited for survival.Darwins theory of common descent suggests a key role for the variation and diversity in the diversification of new species from a common ancestor .According to Mendel ,Generic variations takes place through genes.He gave three laws which are law of dominance ,law of segregation and law of independent assortment .According to law of segregation ,allele pair separate or segregrate  during gamete formation and randomly unite at fertilization and according to law of independent assortment the alleles of two or more different genes get sorted into gametes independently of one another .We can say that the allele , a gamete receives for one gene does not influence the allele received for another .Due to this,the organism produces new combinations of alleles .Crossing over during prophase and independent assortment during anaphase creates sets of chromosomes with new combinations of allele.The Chromosomal basis of inheritance given by Boveri and Sutton ia a fundamental unifying theory of genetics which identifies chromosomes as the carrier of genetic materials .It states that chromosomes which are seen in all dividing cells and pass from one generation to the next are the basis of all genetic inheritance .Over a period of time ,random mutations creates changes in the DNA sequence of a genes which are located in the chromosomes and will pass on to the next generation eventually leading to genetic diversity .And during this exchange of genetic material ,the failure of homologous chromosomes or sister chromatids to separate properly during cell division .The three forms of nondisjunction are :- failure of sister chromatids to separate during meiosis II ,failure of a pair of homologous chromosomes to separate in meiosis I and failure of sister chromatids to separate during mitosis.The results of nondisjunction are :- Monosomy ,Autosomal triosomy and some disorders like Turner syndrome ,Edward syndrome ,Mosaicism syndrome etc also occur .Sometimes mutations occur and the gene is called mutant gene .It is typically composed of a regulatory region which is responsible for turning the gene's transcription on and off at the appropriate times during development ,and a coding region which carries the genetic code for the structure of a functional molecule also generally cahnges .Among this cell division ,transpositions also contribute to genetic variation between individual and populations .DNA transposons are DNA sequence that can move and integrate to different locations within the genome .They are a cause of gene expression alterations .As a newly inserted DNA into active coding sequences ,they can disrupt normal protein functions and cause mutation and due to this transposition genetic diversification tooks place This will result in population genetics that deals with genetic difference within and between populations to examine the adaptions ,speciation and population structure which will occur due to the genetic differences .Thus ,all this phenomenon results in genetic diversity will finally turn the wheel of evolution.