Types of Zygosity

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Understanding:

•  Fusion of gametes results in diploid zygotes with two alleles of each gene that may be the same allele 

   or different alleles

    
Gametes are haploid, meaning they only possess one allele for each gene

When male and female gametes fuse during fertilisation, the resulting zygote will contains two alleles for each gene

  • Exception: Males have only one allele for each gene located on a sex chromosome, as these chromosomes aren’t paired (XY) 


For any given gene, the combination of alleles can be categorised as follows:

  • If the maternal and paternal alleles are the same, the offspring is said to be homozygous for that gene
  • If the maternal and paternal alleles are different, the offspring is said to be heterozygous for that gene
  • Males only have one allele for each gene located on a sex chromosome and are said to be hemizygous for that gene


Types of Zygosity

types of zygosity