Genetics In Offspring

Genetics is the study of heredity and the variation of characteristics inherited from parent to child through generations. Genetics are passed down through chromosomes in DNA which are located in every cell of the body. Each cell contains 46 chromosomes (23 pairs) including the X and Y chromosomes. The only exception to this are the sex cells (sperm and egg) which have 23 chromosomes. Each chromosome carries genes for a certain trait which will be inherited to the offspring. When a new organism is fertilised through intercourse, the 23 chromosomes from the father’s sperm combine with the genes from the mother’s egg. Each pair of genes will find each other and determine which trait will be expressed in the offspring.

To determine which allele will express itself

By using Walther, Johanna, Gerard, and Narelle as examples we can see that there is a 0% chance of any of Walther and Johanna’s children because they are both homozygous for the recessive trait, meaning no dominant genes can be passed down. There is a 75% chance of Gerard and Narelle having children with brown hair because both parents are heterozygous for the dominant trait. The Punnett square shows that there is only a 25% chance of a child being born homozygous recessive because of this.

Colour blindness is a genetic disorder that is evident in 8% of males and 0.64% of females in the world. The large difference in colour blindness from male to female is due to the trait being and X-linked recessive trait, meaning only one X chromosome with the trait is needed for a male to be colour blind. The most common form of colorblindness (red-green colour blindness) occurs because the red or green cones in the eye don’t form correctly or don’t form at all. Depending on which Punnett is incomplete, the person will not be able to see red or green but can see every other colour