Genetics Chapter 12 Flashcards

Study Notes

Heredity and Genetics Overview

Pedigrees are charts used to track the inheritance of traits within families across generations.
Simple recessive heredity is characterized by conditions like phenylketonuria (PKU) and Tay-Sachs disease.
In simple dominant heredity, inheriting just one dominant allele from a parent is sufficient for the trait to manifest in the offspring.

Complex Inheritance Patterns

Complex inheritance includes:
- Incomplete dominance: neither allele fully dominates, resulting in a blending of traits.
- Codominance: both alleles express distinct traits simultaneously in a heterozygote.
- Multiple alleles: more than two allele forms exist for a single trait.
- Sex-linked inheritance: traits associated with genes on sex chromosomes.
- Polygenic inheritance: multiple genes contribute to one trait.

Environmental Influences

Gene expression can be affected by external factors like temperature, nutrition, light, chemicals, and infectious agents.

Genetic Terminology

A carrier possesses a gene that is not visible in the phenotype but can be passed to offspring.
A fetus refers to the developing human from 9 weeks post-conception until birth.
Autosomes are chromosomes that are not involved in determining an individual’s sex.
Codominant alleles will both influence the phenotype in a heterozygous individual.
Incomplete dominance occurs when one allele does not entirely mask the effects of another.
Multiple alleles provide genetic diversity, as a single trait can have three or more variations.
Polygenic inheritance leads to a range of phenotypes due to the interaction of multiple genes.

Chromosomes and Traits

Sex chromosomes are responsible for determining an individual's sex (XX for females and XY for males).
Sex-linked traits are associated specifically with genes located on sex chromosomes, affecting trait expression based on the sex of the individual.
A karyotype is a visual representation of an organism's chromosome sets, arranged by size and shape, useful for identifying chromosomal abnormalities.

Description

Explore key concepts from Chapter 12 on Patterns of Heredity and Human Genetics with these flashcards. Test your understanding of terms such as pedigrees, simple recessive heredity, and simple dominant heredity. Perfect for students seeking to grasp the complexities of genetic inheritance.