What produces the variation in the combinations of alleles on a single chromosome?

Which one produces the variation in the combinations of alleles on a single chromosome?

Genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism’s offspring).

What causes new combinations of alleles?

Recombination is a process by which pieces of DNA are broken and recombined to produce new combinations of alleles. … Crossovers result in recombination and the exchange of genetic material between the maternal and paternal chromosomes. As a result, offspring can have different combinations of genes than their parents.

What causes variation of genes?

Mutations, the changes in the sequences of genes in DNA, are one source of genetic variation. Another source is gene flow, or the movement of genes between different groups of organisms. Finally, genetic variation can be a result of sexual reproduction, which leads to the creation of new combinations of genes.

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What is a variation of an allele?

Allelic variation describes the presence or number of different allele forms at a particular locus (locus or loci = place) on a chromosome (allelic variation is sometimes used more loosely to describe the overall diversity present).

What is the original source of variation among the different alleles of a gene?

Mutations are the original source of genetic variation. A mutation is a permanent alteration to a DNA sequence. De novo (new) mutations occur when there is an error during DNA replication that is not corrected by DNA repair enzymes.

What are the causes of variation?

Major causes of variation include mutations, gene flow, and sexual reproduction. DNA mutation causes genetic variation by altering the genes of individuals in a population. Gene flow leads to genetic variation as new individuals with different gene combinations migrate into a population.

What are 3 reasons to explain genetic variations in meiosis?

Genetic diversity arises due to the shuffling of chromosomes during meiosis.

  • Process of Meiosis. A man produces sperm and a woman produces eggs because their reproductive cells undergo meiosis. …
  • Crossing Over. …
  • Random Segregation. …
  • Independent Assortment.

What are types of variation?

Species Variation

Variation in a species is not uncommon, but there are actually two major categories of variation in a species: continuous variation and discontinuous variation. Continuous variation is where the different types of variations are distributed on a continuum.

How does meiosis cause variation?

During meiosis, homologous chromosomes (1 from each parent) pair along their lengths. The chromosomes cross over at points called chiasma. At each chiasma, the chromosomes break and rejoin, trading some of their genes. This recombination results in genetic variation.

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What are the two main causes of variation?

The two main causes of variation are mutation and genetic recombination in sexual reproduction.

What is variation in gene expression?

Variation in gene expression constitutes an important source of biological variability within and between populations that is likely to contribute significantly to phenotypic diversity. Recent conceptual, technical, and methodological advances have enabled the genome-scale dissection of transcriptional variation.

How can alleles be different?

When the copies of a gene differ from each other, they are known as alleles. … Alleles can sometimes result in different phenotypes (observable traits), with certain alleles being dominant (overriding the traits of other alleles) or, in some cases, multiple alleles acting in a codominant fashion.

How are alleles formed?

When SNPs and other mutations create variants or alternate types of a particular gene, the alternative gene forms are referred to as alleles . … In other words, a given gene can have multiple alleles (i.e., alternate forms). Some genes have just a few alleles, but others have many.

How do single nucleotide polymorphism occur?

A single-nucleotide polymorphism (SNP, pronounced snip) is a DNA sequence variation occurring when a single nucleotide adenine (A), thymine (T), cytosine (C), or guanine (G]) in the genome (or other shared sequence) differs between members of a species or paired chromosomes in an individual.

Are alleles on the same chromosome?

An allele is one of two, or more, versions of the same gene at the same place on a chromosome. It can also refer to one of multiple different sequence variations of several-hundred base-pairs long or longer regions of the genome that code for proteins.

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