- Genotype- the total set of genes (DNA sequences) that control an organism’s chemistry and physiology, as distinguished from the physical appearance, of an organism or a group of organisms.
- Phenotype- the set of physical characteristics of an organism that are passed down to offspring.
- Allele- one constituent part of a pair or series of genes that occupy a specific position on a specific chromosome.
- Heterozygous- having different alleles at one or more corresponding chromosomal loci.
- Homozygous Recessive- having two recessive alleles (generally a trait is only activated with homozygous dominant and homozygous recessive generally makes the animal lose some physical feature)
- Homozygous Dominant- having to dominant alleles (generally
- Heterozygosity- the state of an individual of being heterozygous or the relative number of heterozygous organisms in a population
- Inbreeding- mating between genetically distant populations that leads to a lesser heterozygosity and more homozygosity within and therefore, if the trait has a negative impact on a species, that population will become less and less genetically health
- Identical By Descent- two alleles are identical by descent if they are identical copies of the same allele in an earlier generation
- Inbreeding Coefficient- this is the calculable value by which scientists measure inbreeding.
- Outbreeding- mating between two individuals that are very distantly related that causes an increase in heterozygosity, generally lessening the prevalence of a negative trait within a population to make it more healthy
- Non-random Mating- mating in which individuals are selected for a certain phenotype
- Assortative Mating- positive mating between individuals of a certain phenotype (positive-same phenotype; negative- different phenotypes)
- Sexual Selection vs. Natural Selection- sexual selection- based on phenotypes ; natural selection- nature excludes weak individuals from mating either with environmental stresses or sterility
While researching for this project, we came over many different case studies that showed the effects of inbreeding on a population. One, for instance, involved the New Mexico’s Rio Grande silvery minnow. Inbreeding was preventing its population from increasing because the recessive traits were coming out in the highly endangered species. This was further contributing to the demise of the species along with habitat loss. This demonstrated the problems inbreeding creates.
We are in the process of implementing equations for finding frequencies of genotypes using the frequencies of alleles and then using the genotypic frequencies obtain the inbreeding coefficient. The following are, in order, the equations for determining the genotypic frequencies, the algebra to find the inbreeding coefficient and the already established and accepted equation to calculate the effective population size based on the traits of the organisms:
- P(Homozygous dominant set) = p2 + fpq (the first term is the allelic frequency of the dominant or capital allele; the second term is the factor by which the dominant homozygosity increases or decreases as a result of inbreeding or outbreeding)
- P(heterozygous set) = H = 2pq+ 2fpq (the first term stands for the aA allele set and the second for the Aa allele set because either of the two can be expressed in an offspring)
- P(homozygous recessive set) = q2 + fpq (the first term represents the allelic frequency of the recessive allele; the second term is the factor by which the recessive homozygosity will increase or decrease as a result of inbreeding or outbreeding)
- H= 2pq + 2fpq can be rearranged to form this equation: H= 2pq(1-f) which can be algebraically manipulated into f= 1 - (H / 2pq) which is how in the end we solve for the inbreeding coefficient.