Chapter 8: Mendel and Genetics Flashcards
Dominant
The trait will be displayed even if only one factor specifying it is present
Recessive
The trait will be displayed only in the absence of the dominant
Allele
The different forms of a gene
Homozygous
Having two identical alleles (dominant or recessive) for a trait
Heterozygous
Having two different alleles (one dominant and one recessive) for a trait
Genotype
An organism’s individual collection of genes (allele combination)
Phenotype
The physical traits that appear in an individual as a result of its genotype and from the environment
Monohybrid Cross
a genetic cross that involves one pair of contrasting alleles for a trait
Gene
The set of information that controls a trait; a segment of DNA on a chromosome that codes for a specific trait
Incomplete Dominance
A blended phenotype. One allele is not completely dominant over the other
Chromosomes
Coiled chromatin, 46 are found in human body cells
Diploid
Two copies of each gene
Haploid
One copy of each gene
Testcross
A way to determine the genotype of an individual with an unknown dominant phenotype using a homozygous recessive individual
Gametes
Sex cells; eggs and sperm
Sex-linked
when traits are determined by alleles on the sex chromosomes
The Law of Segregation
When any individual produces gametes, the two copies of a gene separate, so each gamete receives only one copy
Punnett Square
A chart that shows all possible combinations of alleles that can result from a genetic cross
Punnett Square box
Where the genotypes of haploid gametes from one parent are on the horizontal axis, and the genotypes of the other parent are on the vertical axis
Dihybrid cross
a genetic cross that involves two pair of contrasting alleles for traits
Law of Independent Assortment
Where alleles of different genes assort independently of one another during gamete formation
Genotype Ratio
The ratio of genotypes that could appear in offspring
Phenotype Ratio
the ratio of phenotypes that could appear in offspring
Codominance
When two alleles of a gene both produce their phenotypes when present in a heterozygote
Cytoplasmic Inheritance
Present for organelles with their own genomes (mitochondria and chloroplasts)
Non-Mendelian Inheritance
is any pattern of inheritance in which traits do not segregate in accordance with Mendel’s laws
Locus (loci)
is the location of a certain gene on a chromosome
Artificial Selection
Is the process of humans selectively breed plants and animals
Polygenic Inheritance
Is when the phenotype of a heterozygote contains the products of both alleles
