Alu elements have been accumulated in human genome throught mankind evolution, reaching over 1 million copies in genome. They are short, and repetitive DNA fragments found in primates. Each Alu element is known to have 300 base pairs in length. DNA repeats contribute to partial gene deletion or duplications in many cases of hereditary diseases.Alu insertion polymorphisms consists of absence or presence of Alu elements at a particular chromosomal location.(Novick et al,1993)
They are typed by rapid PCR , which are stable polymorphisms. Newly inserted Alu elements rarely ever go trough deletion. The presence of Alu element represent probability that different Alu elements would independently insert into the exact same chromosomal location is negligible. The theory of Hardy-Weinberg equilibrium gives the gene frequencies (proportions of all possible alleles at a given locus)of a given population in absence of evolution.For it to be present within a population,conditions must be met.No net mutations,No difference found in alllele selection, no movement of indivduals into or out of population.(Novick et al, 1993)Population must be infinitely large and mating must be comletely at random.I hypothesize that our class results wont be in equilibrium in regards to the abundance of TPA-25 element.
Alu-TPA-25 is diallelic ;both alleles are distinguishable, two well separated bands of 400Bp (Alu-insertion) which 15 individuals in the class had and 100 Bp (no insertion) 16. The expected genotypic frequencies in this study are calculated with Hardy-weinberg equation:p2 +2pq+q2 where p2 is expected frequecny of ++ individuls in sample and q2 =expected frequency of - - individuals in this sample and 2pq is expected frequency of +-.
Chi-square test was used to examine relationship between observed and expected number of individuals of each genotype. Number of people who have 100bp =16 =16 out of 31 =0. 483. 0. 483)^(1/2)= 0. 6956= q and q is p-1 =0. 304 ; 2pq =0. 422. Statistical values are x2 =6. 7 ; df=1. Expected data is found by taking into account that each individual has two alleles, the total number of (+) alleles = 2x + y and the total number of (-) alleles = 2z +y (Stonekening, 1997). Dividing these numbers by the total number of alleles or 2N, the frequencies for p and q can be determined. The null hypothesis failed to be rejected because chi-square tell us that there is major difference between the expected and observed abundance of TPA-25 elements and it means that the population isnt in equilibrium.
According to conditions of Hardy-Weinberg. Population isnt large enough and people in the class have immigrated at one point from a different country, whether or not there is net mutation or difference in allele selection is uncertain. With all evidence from Hardy-Weinberg equilibrium, results of this experiment are flawed. However, It is possible that DNA samples for apropriate times didn’t heat or cool. .The sample is too small and it consists of only genetics students from our lab. It’s not really random.