Bio topic 7

• What is the first key term in inheritance discussed?

  Genotype
• What does phenotype refer to?

  Expression of genes and environment interaction
• What does homozygous mean?

  Same alleles for a single gene
• What does heterozygous mean?

  Different alleles for a single gene
• When is a recessive allele expressed?

  When no dominant allele is present
• What is codominance?

  Both alleles are equally dominant and expressed
• What is multiple alleles?

  More than two alleles for a single gene
• What is sex linkage?

  A gene located on the X chromosome
• What is epistasis?

  One gene modifies another gene's expression
• What do monohybrid and dihybrid refer to?

  Types of genetic crosses
• What is a monohybrid cross?

  Inheritance of one gene
• What is a dihybrid cross?

  Inheritance of two genes at a time
• What is the probability of a child having cystic fibrosis from two heterozygous parents?

  25%
• What is the probability of having a girl with cystic fibrosis?

  12.5%
• What is the probability of producing a red offspring from two roan cows?

  25%
• What are the possible blood groups in humans?

  A, B, AB, and O
• What is the probability of having blood group A from parents with blood group AB and O?

  50%
• What causes color blindness?

  Recessive allele on the X chromosome
• What is the probability of children being colorblind from a non-color blind male and a female carrier?

  25%
• What is the outcome of crossing two yellow Labradors?

  Four yellow dogs
• What is a dihybrid cross in pea plants?

  Considering two traits simultaneously
• What are the six features needed for genetic crosses?

  Parental phenotype, genotype, gametes, offspring genotype, phenotype, proportions
• What is the expected offspring ratio in a dihybrid cross?

  9:3:3:1
• What does crossing over result in?

  New combinations of alleles in gametes
• What is autosomal linkage?

  Two genes on the same chromosome
• How does autosomal linkage affect inheritance?

  Genes are inherited together
• What happens during meiosis with linked genes?

  Whole chromosome is pulled to create gametes
• What is the outcome of a dihybrid cross with linked genes?

  Only two types of gametes can be made
• What does autosomal linkage mean for genes on the same chromosome?

  They are inherited together.
• How does meiosis affect gamete formation in linked genes?

  Whole chromosomes are pulled to create gametes.
• What types of gametes can be formed from two dominant and two recessive alleles?

  Dominant and recessive alleles together.
• How does autosomal linkage affect the expected phenotypic ratio?

  It can lead to a 3:1 ratio instead of 9:3:3:1.
• What role does crossing over play in genetic variation?

  It creates new combinations of gametes.
• What is the purpose of the chi-squared statistic?

  To investigate differences in frequencies.
• How is the chi-squared statistic used in genetics?

  To compare expected and observed frequencies.
• What is the expected phenotypic ratio for purple and yellow corn?

  3:1 ratio of purple to yellow.
• What does a calculated chi-squared value less than the critical value indicate?

  Accept the null hypothesis.
• What does the Hardy-Weinberg principle predict?

  Allele frequencies within a population.
• What is a gene pool?

  All alleles of all genes in a population.
• What does allele frequency represent?

  Proportion of an allele in the gene pool.