Question

rflp analysis

In this activity you will use RFLP analysis to determine the identity of several individuals. DNA samples were taken from a family consisting of: Mother, Father, Son, Daughter, Grand parents (GP), and three unrelated individuals (UR).Using what you know about Meiosis and inheritance, identify the unmarked lanes from the following options: Why are the Father and Mother lanes not identical? Why are the sibling lanes not identical? Are the Grandparents maternal or paternal? Explain.

Answer 1

3. First of all you have to understand how you and I were made. It really starts when a sperm from your dad and an egg from your mum got together and made you as an individual. Sperm and egg are made by a special form of cell division, which is called meiosis.

Meiosis is special because it turns a diploid, which has two copies of every chromosome, into a haploid, which has one copy of every chromosome. So, when cells goes through the process of meiosis, you take this 46 human chromosomes and you turn it to a cell with one copy of every chromosome, which now means has only 23 chromosomes.

And very importantly, this process of meiosis is random. Every cell that goes through meiosis will inherit one of every chromosome, but whether inherits one from your mother or father is random. So for example, when your father’s cells went through meiosis to make sperm, it was random whether that you inherited chromosome 2 let’s say, from his mother or chromosome 2 from his father.

So now, you can see that when you get an egg and a sperm fusing together, as happened for you and your brothers and sisters, you now see this is now a random collection of chromosomes that aren’t just from your parents but random collection of chromosomes they inherited themselves from their parents.

But it’s actually much more complicated than just random assortment. During the process of meiosis, chromosome 2 will align next to chromosome 2 and chromosome 4 will align next to chromosome 4 and so on and so forth. And this process is absolutely essential to ensure that each haploid sperm or egg inherits exactly one copy of all the different chromosomes.

More than just being essential for the inheritance of every single chromosome, it also allows a very special process to occur whereby chromosomes that are similar but not identical that line up can now exchange pieces of DNA. And this results in making completely unique chromosomes.

So now you've swapped a bit of chromosome 2 that your father inherited from his mum with a bit of chromosome 2 that he inherited from his dad. And the end result is a chromosome 2 that is neither your dad’s, nor is it your grandma’s nor is it your grandfather’s. It’s completely unique. It’s got a bit of both grandma’s and granddad’s and that is the chromosome that your sperm that made you inherited. It’s completely unique to that sperm.

4.

Some believe this difference is due to parents' role as gatekeepers between grandparents and parents.

In spite of strides in gender equality, mothers are still likely to direct their children's activities, and they may give heightened importance to contact with their own parents.

Others hold that the relationship between a woman and her mother-in-law -- the paternal grandmother of her children -- is always going to be complicated.

Possession, so to speak, of a treasured male has been passed from mother to wife. A bit of jealousy and/or competitiveness is natural and may stand in the way of a close relationship, which may in turn stand in the way of closeness between grandparent and grandchild.

Scientists offer a different explanation, an evolutionary thesis, which some observers discount. This scientific explanation holds that mothers are always certain that they are the parents of their children, whereas there may be uncertainty in a father's mind. Before the age of DNA testing, a father had scant means of proving that the child said to be his actually carried his genes. That goes doubly true for a grandfather wondering whether his grandchild is actually his grandchild.

So the maternal grandmother knows with practically 100% certainty that her grandchild is genetically related to her, a maternal grandfather or a paternal grandmother has only half of that certainty and a paternal grandfather has no certainty at all.

Of course, many other factors affect the closeness of a relationship.

Geographical closeness is important, although distance can be overcome. A grandparent's employment status, health, economic status and personality can also play a part. Another factor is the number of grandchildren a grandparent has. A grandparent with many grandchildren may find it difficult to spend quality time and bond with each one.

The preference for maternal grandparents starts early, with maternal grandmothers being more likely to be invited into the delivery room. Similarly, the maternal grandmother is more likely to help out after the birth of a baby, facilitating early bonding with the grandchild. The grandparent who bonds early with a grandchild is more likely to be asked to babysit later on and is more likely to be involved in school activities when the grandchild starts to school.