Microsatellites are currently exploited as markers for paternity testing. A sample paternity test is shown in the following table in which ten microsatellite markers were used to test samples from a mother, her child, and an alleged father. The name of the microsatellite locus is given in the left- hand column, and the genotype of each individual is recorded as the number of repeats he or she carries at that locus. For example, at locus D9S302, the mother carries 30 repeats on one of her chromosomes and 31 on the other. In cases where an individual carries the same number of repeats on both chromosomes, only a single number is recorded. (Some of the numbers are followed by a decimal point, for example, \(20.2,\) to indicate a partial repeat in addition to the complete repeats.) Assuming that these markers are inherited in a simple Mendelian fashion, can the alleged father be excluded as the source of the sperm that produced the child? Why or why not? Explain.

Microsatellite markers are small segments of DNA that consist of repeating sequences of two to five base pairs in length. These sequences are highly variable among individuals, making them excellent tools for genetic analysis.

Used extensively in fields such as forensic science and paternity testing, these markers follow Mendelian inheritance patterns. Each person inherits one marker from their mother and one from their father. Due to the variability in the number of repeats at each microsatellite locus, these markers can generate unique patterns that serve as genetic fingerprints.

For paternity testing, scientists analyze multiple microsatellite markers to determine if there is a match between a child's markers and those of the alleged parent. If the child possesses microsatellite alleles that are not present in the alleged father, it suggests that the individual is not the biological parent.

Genotype inheritance refers to the transmission of genetic information from parents to offspring through their genes. Each parent contributes one allele for each gene, resulting in two alleles at every genetic locus for the offspring.

Due to the diploid nature of human cells, except for sex cells, each person has two sets of chromosomes, one from each parent. This means that for every gene, or genetic marker like microsatellites, a child carries one version from the mother and another from the father.

Matching a child's alleles with those of the alleged parents allows a determination of whether the inheritance pattern is consistent with biological paternity. If alleles present in the child are not found in the alleged father, genetic evidence suggests that the man cannot be the biological father.

Mendelian inheritance is a pattern of inheritance first described by Gregor Mendel in the 19th century, based on his work with pea plants. The principles outlined by Mendel include the laws of segregation and independent assortment.

The law of segregation states that for any given gene, individuals carry two alleles and that these are separated during gamete formation, ensuring that offspring receive one allele from each parent. The law of independent assortment describes how different genes independently segregate from one another when reproductive cells develop.

In the context of paternity testing, Mendelian inheritance means that the genotype of the child, at any given locus, should be a combination of the alleles found in both parents. If the alleles do not correspond to this expectation, Mendelian principles provide a strong genetic basis for exclusion of paternity.

Allele analysis in the field of genetic testing is a process by which specific alleles at various loci are compared and contrasted between individuals. During paternity testing, the analysis focuses on whether the alleles present in a child can be accounted for by the genetic contributions of the mother and the putative father.

In a typical analysis, the alleles of the child are documented and each allele must have a corresponding match with either the mother's or the father's alleles. This type of analysis not only plays a critical role in determining paternity but is also essential in genetic diagnostics, forensics, and anthropological studies.

Effective communication of allele analysis to students or individuals new to genetics involves clarifying that each person possesses two alleles at each locus and demonstrating how these alleles are traced back to parental origins. This understanding forms the cornerstone of interpreting cases of genetic inheritance in paternity testing.