Whole chromosome preservation through generations

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In summary, the conversation focuses on the preservation of whole chromosomes through generations and the likelihood of sharing a complete chromosome with an ancestor. It is determined that during meiosis, crossing over occurs between non-sister chromatids, resulting in a \frac{1}{4} chance of obtaining an intact chromosome. However, it is later clarified that the correct chance is \frac{1}{2} as both homologous chromosomes should not be discriminated against. The conversation also touches on the preservation of allele combinations and the likelihood of an entire chromosome being preserved, leading to the reunion of all alleles for different genes in the next generation.
  • #1
nobahar
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Hello!
I have a peculiar question concerning, as the title states, whole chromosome preservation through the generations.
I'll include my reasoning in case you need to point out any discrepancies.
During meiosis, crossing over occurs between non-sister chromatids. Two of the chromatids from homologous chromosomes are therefore preserved, although they will separate into different gametes. The chances of you obtaining a complete chromosome that has not been subjected to crossing over is [tex]\frac{1}{4}[/tex] for anyone chromosome. Am I correct to assume then, that the chances of your sharing anyone complete chromosome in common with an ancestor is [tex](\frac{1}{4})^n[/tex]? Where n is the number of generations you work backwards?
Thanks in advance.
 
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  • #2
Aplogies, I think it should be [tex]\frac{1}{2}[/tex]. As an 'intact' (i.e. passed on from the previous generation without being subjected to crossing over) chromosome is an 'intact' chromosome, and I suppose I shouldn't discriminate against the two homolgous chromosomes.
Can anyone advance on this? Basically, I am interested in the preservation of allele combinations. From this reasoning, it doesn't seem that unlikely that an enitire chromosome would be preserved, and therefore all the alleles for the different genes that were togeather in the previous generation are togeather again in the next.
 
  • #3


Hello there! Your reasoning is mostly correct. During meiosis, crossing over does occur between non-sister chromatids, resulting in the preservation of two chromatids from homologous chromosomes. However, it is important to note that this process is not perfect and there can still be some genetic variation between generations due to mutations and other factors. Additionally, the chances of obtaining a complete chromosome that has not been subjected to crossing over is not always \frac{1}{4} for every chromosome. It depends on the specific chromosomes and their location on the homologous pair.

To answer your question, the chances of sharing a complete chromosome in common with an ancestor would indeed decrease with each generation, as the likelihood of crossing over and genetic variation increases. However, it is difficult to determine an exact probability as it would also depend on the specific genetic makeup of each individual and their ancestors. It is also important to consider that while some chromosomes may be preserved through generations, others may undergo changes or be lost altogether. Overall, whole chromosome preservation through generations is a complex process and can vary greatly among individuals and families.
 

1. What is whole chromosome preservation?

Whole chromosome preservation refers to the process of maintaining the genetic information contained in an entire chromosome throughout multiple generations of an organism.

2. Why is whole chromosome preservation important?

Whole chromosome preservation is important because it ensures that the genetic information of an organism is passed down accurately to future generations. This is crucial for maintaining genetic diversity and preventing the loss of important traits.

3. How is whole chromosome preservation achieved?

Whole chromosome preservation can be achieved through various methods, such as cryopreservation, which involves freezing and storing cells or tissues, or through selective breeding and controlled mating to maintain specific genetic traits.

4. What are the potential challenges of whole chromosome preservation through generations?

One potential challenge of whole chromosome preservation is genetic mutation, which can occur spontaneously or due to environmental factors. This can lead to changes in the genetic information of a chromosome and affect its preservation over generations.

Another challenge is genetic drift, where random changes in the frequency of alleles can occur in a population over time, potentially leading to the loss of certain genetic traits.

5. How can scientists ensure successful whole chromosome preservation?

To ensure successful whole chromosome preservation, scientists must carefully monitor and manage genetic diversity in a population to prevent inbreeding and maintain a healthy gene pool. They must also use techniques such as genetic testing and assisted reproductive technologies to select and preserve desired genetic traits.

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