The Mendel Lab has its goals to teach you about how the DNA information is inher
ID: 83907 • Letter: T
Question
The Mendel Lab has its goals to teach you about how the DNA information is inherited to offspring from 2 sexually reproducing parents. A key tool Mendel created was the Punnet Square to explain the probability of inheritance. Answer:
1. An offspring can possibly inherit only what is present in the parents. Explain the evolutionary power of a mutation that can occur in an offspring from the combining of alleles during sexual reproduction. Include in your explanation that there is still a probability of what the result of a mutation would be for the offspring.
Explanation / Answer
Answer:
Most genes have one or more versions due to mutations or polymorphisms referred to as alleles. Individuals may carry a ‘normal’ allele and/or a ‘disease’ or ‘rare’ allele depending on the impact of the mutation/polymorphism (e.g., disease or neutral) and the population frequency of the allele. Single-gene diseases are usually inherited in one of several patterns depending on the location of the gene and whether one or two normal copies of the gene are needed for the disease phenotype to manifest.
A mutation is a unique type of abnormality and is the greatest source of genetic variability because it creates a change in the nucleotide sequence composing the DNA. Mutations can be either good or bad.Assuming the daughter cells receive the correct number of chromosomes, problems may arise in the structure of the DNA itself. Mutations involving the rearrangement of the DNA nucleotides is caused in four distinct ways.
A translocation occurs when the DNA double helix is broken and a piece of the chromosome attaches to a neighboring nonhomologous chromosome, making it longer than its homologous chromosome. The donating chromosome is obviously now shorter that its homolog.
Whenever a segment of a chromosome is broken off and lost, the resulting deletion has serious effects on the transmission of the original genetic material.
If a deleted segment returns and joins with a homologous chromosome, a duplication of genes has occurred.
Finally, if a segment breaks loose, reverses, and reattaches in reverse order, an inversion results.
The expression of the mutated allele with respect to the normal allele can be characterized as dominant, co-dominant, or recessive. There are five basic modes of inheritance for single-gene diseases: autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, and mitochondrial.
Genetic heterogeneity is a common phenomenon with both single-gene diseases and complex multi-factorial diseases. It should not be surprising that multiple affected family members may experience different levels of disease severity and outcomes. This effect may be due to other genes influencing the disease phenotype or different mutations in the same gene resulting in similar, but not identical phenotypes.