Genetic Diseases and Key Genetic Terms
This section delves into genetic diseases and introduces essential terminology in genetics. It uses two specific genetic disorders as examples to illustrate inheritance patterns.
Example: Polydactyly, characterized by extra fingers and toes, is caused by a dominant allele, while cystic fibrosis, a disorder affecting cell membranes, is caused by a recessive allele.
The guide provides a comprehensive list of key genetic terms, including DNA, gene, chromosome, genome, allele, dominant, recessive, homozygous, heterozygous, genotype, and phenotype.
Definition: A gene is a small section of DNA on a chromosome that codes for a particular sequence of amino acids, which make a protein.
The section also explains the difference between single gene characteristics and multiple gene characteristics.
Highlight: Most characteristics are controlled by many genes, such as height, while some characteristics are controlled by only one gene, like fur color in mice or color blindness in humans.
The guide then focuses on gender inheritance in humans, explaining the role of sex chromosomes and using a Punnett square to illustrate sex inheritance patterns.
Vocabulary: Human body cells contain 23 pairs of chromosomes, with 22 pairs controlling characteristics and one pair controlling sex. Males have XY chromosomes, while females have XX chromosomes.
