FR Chap 10 Mendel and Patterns of inheritance Flashcards
Heredity
Inheritance
Genetics
The study of heredity
Allele
Alternative form of a gene
Gamete
Egg or sperm sex cell that contains a single set of chromosomes, one from each homologous pair.
Homozygous (example as well)
having identical alleles for a gene.
Heterozygous (example as well)
having different alleles for a gene.
Diploid (human Chromosome Number)
Contain two homologous sets of chromosomes. The total number of chromosomes, 46 in humans, is referred to as the diploid number (abbreviated 2n, as in 2n=46).
Haploid (Human chromosome number)
A cell with a single set of chromosomes is called a haploid. For humans, the haploid number (abbreviated n) is 23.
Phenotype
observed traits of an organism.
Genotype
genetic makeup of an organism; an organism’s combination of alleles.
Homologous Chromosome
one of a matching pair of chromosomes, one inherited from each parent.
Who was he father of genetics?
Gregor Mendel
What was the organism of choice for first studying genetics? A reason why?
Pea plants. Mendel wanted to apply an experimental approach to the question of inheritance.
In a monohybrid true-breeding cross, what ratio of the F1 is always expected?
3:1
In a dihybrid heterozygous cross, what ratio is always expected?
9:3:3:1
Sex-linked trait
Any gene that is located on a sex chromosome.
Carrier
Individual who has one copy of the allele for a recessive disorder and does not exhibit symptoms.
Pedigree
family tree that records and traces the occurrence of a trait in a family.
What is the difference b/w incomplete and codominance? (Examples?)
The alleles Ia & Ib exhibit codominance, meaning that a heterozygote expresses both traits. Note that this is different from intermediate inheritance. The individual’s phenotype is not intermediate, but rather shows the separate traits of both alleles.
Provide an example for Multiple Alleles and Polygenic Inheritance.
Suppose there are three “tall” alleles for each gene (A, B, & C), each of which contributes one “unit” of tallness to the phenotype. These tall alleles exhibit intermediate inheritance with three “short” alleles (X, Y, & Z). A person with genotype AABBCC would be very tall, a person eith genotype AXBBCC would be slighty less tall, & so on.
