Why does random alignment increase genetic variation?
Explain how the random alignment of homologous chromosomes during metaphase I contributes to the variation in gametes produced by meiosis. Random alignment leads to new combinations of traits. The chromosomes that were originally inherited by the gamete-producing individual came equally from the egg and the sperm.
What causes variation in chromosomes?
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 type of genetic recombination is random chromosome alignment resulting in variation?
Crossing-over is the exchange of genetic material between homologous chromosomes. It results in new combinations of genes on each chromosome. When cells divide during meiosis, homologous chromosomes are randomly distributed to daughter cells, and different chromosomes segregate independently of each other.
How does random fertilization produce variation?
Random fertilization increases genetic diversity.
When a male gamete and a female gamete finally meet, each is the result of an immense number of genetic possibilities created during independent assortment and crossing over. Human diploid cells have 23 pairs of chromosomes.
What is meant by random alignment?
Random alignment leads to new combinations of traits. The chromosomes that were originally inherited by the gamete-producing individual came equally from the egg and the sperm. In metaphase I, the duplicated copies of these maternal and paternal homologous chromosomes line up across the center of the cell.
What is likely to happen during alignment of chromosomes?
During metaphase, the cell’s chromosomes align themselves in the middle of the cell through a type of cellular “tug of war.” The chromosomes, which have been replicated and remain joined at a central point called the centromere, are called sister chromatids.
What is a chromosome variation?
Numeric sex chromosome variations refers to differences in the number of sex chromosomes that may be present in an individual’s body cells .
When does random fertilization occur?
Random fertilization refers to the fact that if two individuals mate, and each is capable of producing over 8million potential gametes, the random chance of any one sperm and egg coming together is a product of these two probabilities – some 70 trillion different combinations of chromosomes in a potential offspring.
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.
How does random assortment contribute to genetic variation?
Genetic variation is increased by meiosis
Because of recombination and independent assortment in meiosis, each gamete contains a different set of DNA. … A gamete will end up with 23 chromosomes after meiosis, but independent assortment means that each gamete will have 1 of many different combinations of chromosomes.
How does recombination affect genetic variation?
Recombination effectively ‘shuffles’ maternal and paternal DNA, creating new combinations of variants in the daughter germ-cells (Figure 2). Figure 2 Recombination contributes to human genetic variation by shuffling parental DNA and creating new combinations of variants.
What does recombination do to genetic variation?
Recombination is a process by which pieces of DNA are broken and recombined to produce new combinations of alleles. This recombination process creates genetic diversity at the level of genes that reflects differences in the DNA sequences of different organisms.
What is random mating in biology?
In genetics, random mating (panmixia) involves the mating of individuals regardless of any physical, genetic, or social preference. In other words, the mating between two organisms is not influenced by any environmental, hereditary, or social interaction. Hence, potential mates have an equal chance of being selected.
How do the random distribution of chromosomes and crossovers create more variation in the resulting gametes?
When cells divide during meiosis, homologous chromosomes are randomly distributed during anaphase I, separating and segregating independently of each other. This is called independent assortment. It results in gametes that have unique combinations of chromosomes.
What is the nature of chromosomes that align themselves on the metaphase plate in metaphase I?
In metaphase I, the tetrads line themselves up at the metaphase plate and homologous pairs orient themselves randomly. In anaphase I, centromeres break down and homologous chromosomes separate. In telophase I, chromosomes move to opposite poles; during cytokinesis the cell separates into two haploid cells.