Ayesha's+Group

Introduction

Polymorphism is the condition of having more than one allele with a frequency of over 5% old fashioned definition any variation will do in the population. Genetic variation can have a direct affect on the morphology or colour of an organism in a natural population sounds like a borrowed definition . There can be many reasons for polymorphism, and the resulting genetic variation; mutation is the only reason , genetic drift, selection and/or gene flow these three explain its frequency and geographic distribution . Polymorphism is a very complicated phenomenon in genetics and to research polymorphism on humans is quite difficult; it can take a considerable time to collect data from PCR and any experiment carried out with humans requires written ethical approval, which can take time to gain from an ethical board. To understand the phenomenon of polymorphism it is much easier to use primitive species like //Cepaea// because their genetic structure is simple is there any evidence that its simpler than humans?  and their findings can be applied to humans only? .

//Cepaea // is a cross-fertilizing hermaphrodite. There are four species: //C.nemoralis//, //C. hortensis//, //C. vindobonensis// and //C. sylvatica//. relevant? //Cepaea,// which are widespread in Europe, North America and Russia. relevant?  They are also isolated according to their habitat or difference in time activity relevant? . All of the species have considerable differences in the anatomy, especially//C.nemoralis//, the most well known polymorphic members of the European fauna. relevant?  Its shell is polymorphic for colour, presence, number and appearance of the bands. The genetics of most of the //C. nemoralis// shell polymorphism is well understood. However, something that is difficult to understand is the wide polymorphism of //Cepaea// better, explain why its difficult and the advantages of it for the environment and for them need there be any . To find out the reasons for what? <span style="font-family: Arial,sans-serif; line-height: 17px;">, forward observations are necessary unclear <span style="font-family: Arial,sans-serif; line-height: 17px;">. The visible polymorphism of //Cepaea// provides an excellent opportunity to study the interactions between ecology and genetics (Jones et al., 1977) and it is of great advantage that they have a small dispersal distance so populations of different generations can be investigated easily unclear, different generations are present? <span style="font-family: Arial,sans-serif; line-height: 17px;">.

<span style="color: black; font-family: Arial,sans-serif; font-size: 10pt; line-height: 13.15pt; margin-bottom: 0cm;">The aim of this experiment is to determine the extent of genetic drift and natural selection on the snail species, //C. nemoralis// according how can drift be 'according to different envts'? <span style="font-family: Arial,sans-serif; line-height: 17px;"> to different environments and to identify the frequency of phenotypically expressed alleles. <span style="color: black; font-family: Arial,sans-serif; font-size: 10pt; line-height: 115%;">In this investigation we will sample snails from two different locations; grassland and shrubland as it is these areas that have obvious physical differences. We will classify the snails based on phenotypic differences and record colour of snail shells (brown, pink or yellow) and the banding number (five to one). Samples were taken three times within each environment for both factors; banding and colouring. Three replicates for each set were an intro should set out the logic of the design, not the details in the past tense necessary for accuracy. <span style="color: black; font-family: Arial,sans-serif; font-size: 10pt; line-height: 115%;">We will aim to collect at least 50 snails per set providing a sufficiently large sample size for our results and discussion. Depending on the data we find at the snail site we may also sample the number of live versus dead snails in each location. This analysis should provide a lot of information about the logic the analysis can't reveal the logic! (unless snails are cleverer than I thought) <span style="font-family: Arial,sans-serif; line-height: 14px;"> of the wide polymorphism of //Cepaea//.

<span style="color: black; font-family: Arial,sans-serif; font-size: 10pt; line-height: 13.15pt; margin-bottom: 0cm;">If there is a bottleneck effect, the banding will have spread through different populations and generations due to chance, thus resulting in no real pattern being distinguishable this seems wrong. Bottlnecks can produce a local population highly differentiated from others <span style="font-family: Arial,sans-serif; line-height: 17px;">. If it is due to gene flow there will be differences between each of the transects of the valley why? Seems wrong as gene flow homogenises allele freq. <span style="font-family: Arial,sans-serif; line-height: 17px;">. If however, what we observe is due to selection you would observe specific what does that mean? <span style="font-family: Arial,sans-serif; line-height: 17px;"> differences between different areas (shrubland, grassland) so banding would be specific to specific areas. explain logic

<span style="color: black; font-family: Arial,sans-serif; font-size: 10pt; line-height: 13.15pt; margin-bottom: 0cm;">It is hypothesised that if the effects are due to selection when statistical analysis has taken place of raw data; there should be distinct differences between the colour of the shell and number of bands at each location. seems wrong. Both selection and drift lead to significant differences between different localities

<span style="color: black; font-family: Arial,sans-serif; font-size: 10pt; line-height: 13.15pt; margin-bottom: 0cm;">References

<span style="color: black; font-family: Arial,sans-serif; font-size: 10pt; line-height: 115%;">Jones, J. S., Leith, B. H. & Rawlings, P. (1977) Polymorphism in Cepaea: A Problem with Too Many Solutions? //Ann. Rev. Ecol. Sys, 8,// 109-143

**Group secretary: Ayesha Begum** bt09180@qmul.ac.uk

**Group members**: Aditi Tanna bt09017@qmul.ac.uk Ado Gubaljevic a.gubaljevic@stu10@qmul.ac.uk Karmdeep Shoker bt09119@qmul.ac.uk Maureen Islam bt09462@qmul.ac.uk Shilpi Sheth bt09376@qmul.ac.uk George Ebunam ef08028@qmul.ac.uk