SAMPLE Developmental Psychology

thymine , guanine , and cytosine . These four bases are put into pairs. Adenine is paired up with thymine, while guanine is paired with cytosine. Hereditary information has a basic unit called a gene . Genes are what chromosomes are made up of. They are the individual segments of chromosomes. Individuals are known to have around 100,000 genes. All genes are different, have specific DNA, and carry genetic codes from the parent to the child. The 23 rd chromosome is called the sex chromosome . Females have two X chromosomes (XX), while males have one X and one Y chromosome. Two types of components make up a person’s genetic makeup. One is called the genotype , and the other is called the phenotype . The genotype makes up the genetic makeup, which includes 2 types of genes. The phenotype component is considered the observable trait that can be seen, including eye color, hair color, and a person’s height. Some genes are present in the genotype that are not observable. These unexpressed genes are called carriers . The unexpressed genes can be passed on to other children. Genes that interact with one another are called the gene-gene interaction , and they can also interact with their environment, called the gene-environment interaction . Let’s look at the gene-gene interactions: Gene-Gene Interaction ● Additive: This shows the contribution of multiple genes ○ Example : A tall woman and a short man have a child of medium height. ● Dominant-Recessive: Genes known to be non-additive, meaning they are one or another. ○ Example: A person with a dominant gene for brown eyes can be a carrier for blue eyes. Brown eyes are typically shown since they are the dominant gene. ● Incomplete Dominance: This phenotype is not entirely controlled by the genotype. ○ Example: Some red flowers and white flowers may produce pink flowers in a variety of pink hues. ● X-Linked Genes: Genes that are on the X chromosome can be dominant or recessive and happen to be more common in men. ● Dominant Genes: Traits/Genes that are always expressed. ● Recessive Genes: Traits/genes that are not expressed.

○ Example: Baldness in men is carried on the X chromosome. ● Polygenic traits: Traits influenced by more than one gene. ○ Example: Height, skin color

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