Genetic inheritance and pedigrees Flashcards
(15 cards)
What is a gene?
A section of DNA that gives instructions for making a specific protein or trait.
What is a trait?
A characteristic or feature of an organism, like eye color or height.
What is an autosome?
A chromosome that is not a sex chromosome; humans have 22 pairs of these.
What is a sex chromosome?
A chromosome that determines if a person is male (XY) or female (XX).
What is an allele?
A different version of a gene.
For example, there can be a gene for eye color, and the alleles could be blue or brown.
What does homozygous mean?
When both alleles for a gene are the same, like BB or bb.
What does heterozygous mean?
When the two alleles for a gene are different, like Bb.
What is a dominant allele?
An allele that shows its trait even if only one copy is present (like B in Bb).
What is a recessive allele?
An allele that only shows its trait if two copies are present (like b in bb).
What is a genotype?
The combination of alleles an organism has, such as BB, Bb, or bb.
What is a phenotype?
The physical appearance or trait that results from the genotype (like having brown eyes).
What are Punnett squares?
A diagram used to predict what traits offspring might have based on the parents’ genes.
What is codominance?
When both alleles are shown equally in the phenotype.
For example, a flower with red and white patches.
What is incomplete dominance?
When neither allele is fully dominant, and the result is a mix (like red and white making pink).
What is a pedigree chart?
A diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism from one generation to the next.
