If gene frequency between genes a and c is 2%; b and c is 13%; b and d 4%; a and b 15%; c and
d 17 and a and d 19%. What is the sequence of genes in a chromosome ? Explain your answer
with the help of a diagram.
Cannot diagram on these posts.
unknown
To determine the sequence of genes on a chromosome, we can use the information provided about the gene frequencies between different gene pairs.
Let's first list down the given gene frequencies:
- Gene frequency between genes a and c: 2%
- Gene frequency between genes b and c: 13%
- Gene frequency between genes b and d: 4%
- Gene frequency between genes a and b: 15%
- Gene frequency between genes c and d: 17%
- Gene frequency between genes a and d: 19%
To represent this information visually, we can use a chromosome diagram. Let's assign each gene a different letter as follows:
- Gene a
- Gene b
- Gene c
- Gene d
Now, let's organize the information about gene frequencies on the chromosome diagram:
2% 4% 13% 15% 19% 17%
a ----- c ----- d ----- b ----- a ----- d
From the given gene frequencies, we know that the frequency between genes a and c is 2%. So, we place gene c next to gene a with an arrow indicating a connection. The same process is followed for the rest of the gene pairs:
- Gene frequency between genes c and d is 17%, so gene c is followed by gene d.
- Gene frequency between genes b and d is 4%, so gene d is followed by gene b.
- Gene frequency between genes a and b is 15%, so gene b is followed by gene a.
- Gene frequency between genes b and c is 13%, so gene a is followed by gene c.
- Gene frequency between genes a and d is 19%, so gene c is followed by gene d.
The final sequence of genes in the chromosome, based on the given gene frequencies, is:
a -> c -> d -> b -> a -> d
Note: This is a simplified example to help understand the concept. In reality, the arrangement of genes on a chromosome is much more complex, with many more genes involved.
To determine the sequence of genes in a chromosome, we need to analyze the given gene frequencies between pairs of genes. To make it easier, let's assign a letter to each gene: a, b, c, and d.
Based on the provided gene frequencies, we can construct a diagram called a chromosome map or linkage map. In this map, we will represent the genes as points on a line, with the distances between them proportional to the gene frequencies. The closer two genes are, the higher the gene frequency between them.
Let's start by drawing our chromosome map with the four genes: a, b, c, and d.
```
a b c d
```
Next, let's consider the gene frequencies provided and draw lines proportional to those frequencies. We will use the following scale: every 1% in frequency will correspond to a distance of one unit on our map.
```
a b ——————— c d
| / |
| / |
a ----------- d
```
According to the given gene frequencies:
- The frequency between genes a and c is 2%. We draw a line between a and c, representing this frequency.
- The frequency between genes b and c is 13%. We draw a line between b and c, proportional to this frequency.
- The frequency between genes b and d is 4%. We draw a line between b and d, proportional to this frequency.
- The frequency between genes a and b is 15%. We draw a line between a and b, proportional to this frequency.
- The frequency between genes c and d is 17%. We draw a line between c and d, proportional to this frequency.
- The frequency between genes a and d is 19%. We draw a line between a and d, proportional to this frequency.
Now, we can observe the layout of our chromosome map and see the sequence of genes on the chromosome:
```
a ——— b ——— c ——— d
```
Therefore, the sequence of genes on the chromosome is: a, b, c, d.
Note that this is a simplified representation, and in reality, genes are located on chromosomes with much more complex structures. The examples above demonstrate a basic application of gene frequencies to determine the gene sequence on a chromosome.