Chapter 14 - Mendel & Genetics

What is genetics?

Study of heredity (Mendel’s pea plant experiments)

What is heredity?

Transmission of traits from one generation to the next (pea flower color passed from parents to offspring)

What is a character?

A observable feature, like flower color or seed shape

What is a trait?

Versions of the observable feature, like purple flowers or round seeds

What is a gene?

A DNA sequence coding for a character (gene for flower color)

What is an allele?

Versions of genes (P = purple, p = white)

What is hybridization?

Crossing two true breeding varieties

What is codominance? Example?

Both alleles expressed (AB blood type)

What are multiple alleles? Example?

More than 2 alleles exist (ABO blood system)

What is pleiotropy? Example?

One gene affects many traits (sickle cell, cystic fibrosis)

What is epistasis? Example?

One gene masks another (coat color: one for gene pigment, another for expression)

What is polygenic inheritance? Example?

Many genes control one trait (skin color, height)

What are multifactorial traits? Example?

Traits influenced by genes and environment (diabetes, heart disease)

What is pedigree used for?

To track inheritance of traits across generations

What does homozygous mean?

Two identical alleles (PP or pp)

What does heterozygous mean?

Two different alleles (Pp)

What is phenotype?

Observable traits (purple flowers)

What is genotype?

Genetic makeup (PP, Pp, or pp)

What is dominant allele?

Determines pheotype in heterozygote (P = purple)

What is a recessive allele?

Masked in heterozygote (p = white)

What is the Law of Segregation? (Monohybrid cross)

2 alleles separate during gamete formation (Pp, gametes: P or p)

What is the Law of Independent Assortment? (Dihybrid cross)

Alleles for different genes assort independently

What is the multiplication rule?

Multiply probabilities to find the chance of two events happening together

What is the addition rule?

Adds probabilities to find the chance of one event OR another happening

What is true breeding?

Organism that through many generations of self fertilization only produces offspring with the same trait (homozygous)

What is F1 generation?

First offspring from the hybrid cross

What is F2 generation?

Offspring from crossing two hybrids