Cells and DNA ^🔗

• Inside almost every one of your body cells is a nucleus - this nucleus contains your DNA
• Pātai: What does DNA stand for?
  • Deoxyribonucleic Acid
• Every cells contains a full set of DNA - the instructions to do everything.
  • This means your eye cells contains instructions on how to be a toenail, for example.

DNA and Genes ^🔗

• Your DNA is stored in 23 different pairs of chromosomes
• You got one of each pair from your parents
• The DNA stored in each chromosome is split into sections
• A section of DNA is called a gene

Inheritance ^🔗

• We inherit one of each chromosomes from our parents
• This is why we look like a mix of them
• This is why we can inherit genetic diseases from them too

Task / Ngohe: Trait Survey ^🔗

1. Collect a trait survey sheet from the front
2. Fill out your own column
3. Take it home to survey your parents and siblings (where possible)!
4. Are there any differences? Anything specific jump out at your?

Dominant and Recessive Alleles ^🔗

• Because you get a mix of alleles from your parents but display only one trait, some alleles must be dominant!
• For example, you might get the brown eye gene from one parents, and green eye gene from the other. You eyes turn out brown. The brown eye gene is dominant.
• Pātai: If my dad has green eyes, and my mum has brown eyes, how can I have blue eyes?
  • They each carry a blue eye gene, but it is recessive! The brown overrides it.

• Dominant: A allele that expresses itself over another
• Recessive: A allele that is overridden and not expressed in the presence of another.

Punnet Squares ^🔗

• Dad has two brown eye (B) alleles
• Mum has one brown eye (B) and one blue eye (b) allele
• Brown eyes is dominant to blue eyes
• Pātai: What are the possible alleles combinations for the children?
• Pātai: What colour eye does each possible child have?

Phenotype and Genotype ^🔗

• Mum and Dad both have one brown eye (B) and one blue eye (b) allele
• Brown eyes is dominant to blue eyes
• Phenotype: The physical presentation of the genes
• Genotype: The combination of genes that a organism has
• Pātai: What is the probability of having brown or blue eyes?
• Pātai: What is the probability of having each genotype?

^🔗

• Dad has one brown eye (B) and one blue eye (b) alleles
• Mum has two blue eye (b) alleles
• Brown eyes is dominant to blue eyes
• Fill in the Punnett square
• Pātai: What is the probability of having each phenotype (brown or blue)?
• Pātai: What is the probability of having each genotype?

^🔗

• Dad carries the the allele for a disease but does not have it (Dd)
• Mum does not carry the allele for the same disease (dd).
• Pātai: Is the disease dominant or recessive?
• Pātai: What is the probability of having the disease or not?
• Pātai: What is the probability of having each genotype?

Task / Ngohe: Dominant and Recessive Worksheet ^🔗