How does crossing over and independent assortment insure genetic variability?

Answer 1

It doesn't always. When crossing over occurs sections of nucleotide bases are switched. Lets take for example you have an original DNA of TTCTCCGATAGT and crossing over occurs to change this into TTCATGGATTCT. When this is now read by the mRNA only ATG will become a different protein meanwhile AGT on the original will be made into the same protein. This is because you have to look at the codon table to see which codons become which protein. Different codons may produce the same proteins so crossing over does not always ensure genetic variation but is gives genetic variation a more likely probability of happening. As for independent assortment, this doesn't lead to genetic variation. Really independent assortment will just lead to different phenotypes being expressed.

Answer 2

This is a long but simplified answer. The answer is kind of complex, but I tried to keep it as simple as possible without losing the actual truth.

Sometimes two chromosomes swap sections of DNA during meiosis. In meiosis the cells that result are gametes and these are the cells that will be passed on the the next generation. Humans and many other organisms have two copies of each chromosome (some have more than two), but the chromosomes are a little bit different. When the DNA that is traded is between the two different copies (homologous chromosomes)it is called crossing over. If it is between two chromosomes that are not copies of each other(nonhomologous chromosomes) it is called translocation. So if copy A of chromosome 1 trades some DNA with copy B of chromosome 1 it is called crossing over. If copy A of chromosome 1 trades DNA with copy A (or B) of chromosome 4 it is called translocation.

Independent assortment means that the pairs of homologous chromosomes don't always split up the same way when the gametes are formed. That means that just because a gamete has copy A of chromosome 1 it won't always have copy A of chromosome 2 and so on.

Both of these things together contribute to variability by helping to mix things up in the gametes. Some genes on a chromosome work together to express a trait. If one of those genes has been moved to a different chromosome, the trait won't be expressed. Sometimes the genes don't need to be on the exact same chromosome to work together, but can be on homologous chromosomes. If the gamete combines with a gamete without one of the genes, the trait won't be expressed. These are only a couple of ways that genetic variability can come from crossing over and independent assortment. There are so many ways to recombine our DNA that it is a wonder that we are as much alike as we are.

Answer 3

Because those functions of the life cycle, are too many different functions.

Answer 4

genes and genotypes and swapped inside the body due to a mutation of codons. due to this effect they are now all mixed up so when they re join they are different thus genetic variation!