what are the causes and effects of genetic variation in human?

Answer 1

causes:radiation, meiosis (crossing over, random assortment, base pairing error, or the loss or gain of a chromosome)

effects:radiation can cause normal cells to become cancerous cells, which replicate uncontrollably, which is sometimes fatal.

the loss or gain of a chromosome can be devastating, and will either result in a nonfunctioning embryo, a deformed embryo, or possibly one with very few differences from normal human beings.

the random genetic variations that occur during meiosis are almost always positive. the differences in each human's DNA causes the human population to have a very vast set of differences, which can defend our population. If a devastating disease were to hit the human population, a population with very uniform genetic traits would be doomed most likely doomed, since a uniform gene pool means that either all of the population will be safe, or all will perish (most likely all will perish). with a diverse gene pool, there is a better chance that some individuals will be immune to that disease because of their genes, helping to protect the human population from being devastated by a single disease.

Answer 2

Ultimately all genetic variation derives from mutation of DNA and most mutation is bad (or neutral). In the event it is good (improves the evolutionary fitness of the carrier of this mutation) it can increase in the population. Unfortunately the effects of the majority of mutations are negative because they usually break the protein that the DNA codes for which results in a loss of function.

The one other source of Genetic Variation in populations is Gene Flow which is the migration of alleles from other populations but ultimately the new allele derived at some point from mutation.

The importance of this question is that genetic variation provides the grist for evolution (a change in allele frequencies of a population over time). Mutation and Gene flow bring in new variants to a population usually at low frequencies, the proportion of these alleles in these population can change over time due to Natural Selection and Genetic Drift.

Many people who answered this question suggests a central role for recombination during Meiosis. I would argue against this answer. It does give the appearance of variation by bringing new combinations of genes together which can interact to create new phenotypes which, in classical Darwinian evolution, is what selection acts to change ("Selction acts on individuals to change phenotypes"). In the late '70's Richard Dawkins created a stir by saying that Selection acts on the gene directly and that recombination actually helps this by breaking up gene combinations over long periods of time. I favor this interpretation.

Answer 3

Mutations that occur in the DNA sequence of one gene. Genes code for proteins, the molecules that carry out most of the work, perform most life functions, and even make up the majority of cellular structures.

When a gene is mutated so that its protein product can no longer carry out its normal function, a disorder can result. There are more than 6,000 known single-gene disorders, which occur in about 1 out of every 200 births. Some examples are cystic fibrosis, sickle cell anemia, Marfan syndrome, Huntington’s disease, and hereditary hemochromatosis.

Answer 4

i am a sophmore in high school so you might want to check on this but, this is what i remember from bio honors last year..
genetic variation comes from a stage of meiosis that is basically "genetic shuffling" or dna replication and recombination.
the variations in things like, hair color, facial features ect. are all decided on how those dna strands are recombined.

Answer 5

The reshuffling of alleles is very popular both as a method of genetic development but as a recreational activity.

Answer 6

Causes are replication errors and radiation damage. Effects are random mutations, some good, some bad.

Answer 7

simple answer: mutation and recombination... the drivig forces of evolution.

Answer 8

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