Inheritance Flashcards
(31 cards)
What is a gene?
A sequence of bases of DNA that code for a polypeptide.
What is an allele?
a different version of a gene
What is a loci?
the fixed position where the allele of each gene is found
What is a genotype?
The genetic constitution of an organism.
What is a phenotype?
The expression of the genetic constitution of an organism and its interaction with the environment.
What are dominant alleles?
Alleles that only need one copy to be expressed.
What are recessive alleles?
Alleles that need copies to be expressed.
What are codominant alleles?
Both the alleles are expressed in the phenotype as neither is recessive.
What does homozygous mean?
The alleles are the same.
What does heterozygous mean?
The alleles are different.
What is monohybrid inheritance?
The inheritance of a characteristic which is controlled by a single gene.
What is the expected ratio for the offspring of the F2 generation of parents with the phenotype NN and nn?
3:1
What are multiple allele crosses?
Inheritance of a characteristic when there are more than two alleles of the same gene.
Parents with blood group AB and blood group O reproduce. What is the probability that they will have offspring with the blood group A?
25 percent.
What is dihybrid inheritance?
The inheritance of two characteristics that are controlled by two different genes.
What are the female sex chromosomes?
XX
What are the male sex chromosomes?
XY
What is sex linkage?
The inheritance of a characteristic that is controlled by genes on sex chromosomes.
Why are males more likely to inherit genetic conditions like haemophilia and colour blindness?
The Y chromosome is smaller so most of the sex-linked genes are on the X chromosome. Since males only have one X chromosome they often only have one allele for sex-linked genes and those are usually always expressed even if they are recessive. This means that males are more likely to have recessive phenotypes and the disorders caused by recessive genes include haemophilia and colour blindness.
What is autosomal linkage?
The inheritance of genes that are on the same chromosome.
What are autosomes?
Any chromosome that isn’t a sex chromosome.
Why are genes close together on the same autosome said to be linked?
The genes will stay together during independent segregation and their alleles will be passed on to their offspring together.
Why might some of the genes on the same autosome not be inherited together?
Crossing over during meiosis splits them apart.
What is epistasis?
When the expression of one gene makes the expression of another gene.
