genetics terms
Gene
1. a segment of DNA that determines or helps to determine a trait. 2. give instructions for building a particular protein.
Dominant
1. an allele that is always expressed when it is present. 2. usually represented by capital letters, such as F.
Recessive allele
1. an allele that is not expressed when the dominant allele is present. 2. These alleles are usually represented by lowercase letters, such as f.
Homologous Chromosome
Chromosomes that are similar in size, shape, and genetic material pair up
If the alleles are expressed as BB, is this a dominant or a recessive trait?
Dominant
If the alleles are expressed as Bb, is this a dominant or a recessive trait?
Dominant
Genetics
the science that involves patterns of inheritance
What is an organism in which two alleles for a trait are different?
Heterozygous
Chromosomes are divided into 2 groups. What are they?
Sex Chromosomes and Autosomes
Heterozygous
having two alleles that are different. (One dominant and one recessive) EXAMPLE: Bb
Homozygous
having two alleles that are the same. (Both are either dominant or recessive) EXAMPLE: BB or bb
Purebred
An organism that has identical alleles for a particular trait.
2. Organisms with different genotypes can have the same phenotype. For example, an FF mouse and an Ff mouse both have black fur.
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Autosomes
1) determine characteristics that do not include gender. 2) 22 pair of homologous chromosomes
Sex Chromosomes
1) determine the gender of the organism and also carries genes for some traits 2. 23rd pair of chromosomes differ in males (XY) and females (XX), this determines the gender
Trait
1. a characteristic of an organism. 2. Examples of these include skin color, eye color, hair, allergies, and many others.
Allele
1. one of two or more forms that a gene could take. 2, Dominant ones are always expressed in the organism when they are present 3. Recessive ones are only expressed when the dominant one is not present.
Genotype
1. the genetic makeup of an organism. 2. possessed by an organism are represented by symbols. For example, a mouse might have the genotype FF, Ff or ff.
Hybrid
1. the offspring of genetically different parents 2. For example, the offspring of pure FF and ff parents is an Ff hybrid.
Inheritance
1. the passage of genetic material from parents to offspring. 2. For each gene, an organism receives one allele from each parent.
Incomplete dominance (partial dominance)
1. the phenomenon in which one allele is not completely dominant over the other 2. resulting in a new phenotype 3. EXAMPLE: Pink flowers
Phenotype
1. the physical appearance of an organism.
Codominance
2. the phenomenon in which two alleles contribute to a phenotype 2. two different proteins are produce and detected 3. EXAMPLE: AB Blood type
What are different versions of a gene for the same trait called?
Alleles
If the alleles are expressed as bb, is this a dominant or a recessive trait?
Recessive
Sex-linked traits
Triats controlled genes located in the sex chromosome
Pedigree
a chart used to trace the inhertance of a specific trait through several generations in a family.
Testcross
is a deliberate genetic cross that can be used to determine whether a plant or animal is homozygous or heterozygous for a particular trait.