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Genes and Alleles

 
11.3 Genes and Alleles
 
Definition of Locus
A specific location of a gene in a chromosome.
 
Locus, Gene and Allele on A Pair of Homologous Chromosomes
  • Each chromosome carries many genes.
  • In human, the number of genes that code for proteins in a set of haploid chromosome is estimated to be 25 000.
  • Allele which represents a gene is located at the same locus as the gene.
  • The diagram below shows shows five genes with their respective alleles on specific loci of a pair of homologous chromosome.

This image shows a pair of homologous chromosomes. Key features include: - **Alleles**: Represented by letters (A, a, C, c, F, f, M, m) on the chromosomes. - **Centromere**: The central part where the chromosomes are connected. - **Homozygous dominant (FF)**: Same alleles on both chromosomes. - **Homozygous recessive (jj)**: Same alleles on both chromosomes. - **Heterozygous (Mm)**: Different alleles on each chromosome. - **Loci**: Specific locations on the chromosomes where genes are found. The image illustrates the genetic composition and variation within the homologous chromosomes.
 

 

 

 

 

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Chapter : Inheritance
Topic : Gene and Allele
Form 5 Biology
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