Chromosomal Basis Of Inheritance Flashcards
What is codominance?
Codominance is a type of inheritance where two different versions of a gene (alleles) are expressed equally and produce different traits in an organism.
What does homozygous mean?
Homozygous refers to an organism that has two identical copies of a particular gene.
What does heterozygous mean?
Heterozygous refers to an organism that has two different copies of a particular gene.
What is phenotype?
Phenotype is the observable characteristics or traits of an organism.
What is a polygenic trait?
A polygenic trait is a characteristic that is controlled by multiple genes.
What is pleiotropy?
Pleiotropy is the phenomenon where a single gene influences multiple, seemingly unrelated phenotypic traits within an organism.
What is epistasis?
Epistasis is a biological phenomenon that occurs when the expression of one or more genes modifies the expression of another gene.
What is a test cross?
A test cross is a cross with a homozygous recessive to determine the genotype of an unknown.
What is a dihybrid cross?
A dihybrid cross is a cross that involves two different gene pairs.
What is incomplete dominance?
Incomplete dominance is a pattern of inheritance where two alleles blend to create a new phenotype in the offspring.
How many pairs of Autosomes do humans have?
22 pairs of autosomes
Humans have one pair of sex chromosomes (XX female, XY male)
Nondisjunction
Failure of chromosomes to separate properly during meiosis, resulting in aneuploidy
Aneuploidy
Abnormal number of chromosomes (e.g.,monosomy, trisomy)
Monosomy
Trisomy
Monosomy: Missing one chromosome (2n - 1).
Trisomy: Extra chromosome (2n + 1).
Polyploidy
Organism has more than two complete sets of chromosomes
Sex linked traits
Traits associated with genes located on sex chromosomes
What is Down Syndrome?
Down Syndrome (Trisomy 21) is caused by an extra copy of chromosome 21. It is associated with developmental delays, distinctive facial features, and varying levels of intellectual disability.
What is Turner Syndrome?
Turner Syndrome (XO) occurs in females with only one X chromosome. It leads to short stature, infertility, and sometimes heart and developmental issues.
What is Klinefelter Syndrome?
Klinefelter Syndrome (XXY) occurs in males with an extra X chromosome. Symptoms may include reduced testosterone levels, infertility, and some feminine physical traits.
What is the Law of Segregation?
During meiosis, alleles for each gene separate so that each gamete carries only one allele for each gene.
What is the Law of Independent Assortment?
Genes located on different chromosomes assort independently during gamete formation.
What did Thomas Hunt Morgan’s experiments with fruit flies establish?
Morgan’s work established that genes are located on chromosomes and that some traits are sex-linked.
What evidence did Morgan’s experiments provide?
His experiments provided evidence for linkage and crossing over.
