fundamental concepts of genetics

Question 1

____________ is a population measure defined as the proportion of individuals in the population carrying the allele who actually express the phenotype

Answer 1

penetrance

*probability a person will express the phenotype

*expressed as a percentage

*more population based

Question 2

____________ is defined as varying phenotypes despite identical genotypes

Answer 2

expressivity

*more indivdual based

Question 3

explain the difference between constant and variable expressivity

Answer 3

constant = all individuals with a given phenotype express the same phenotype

variable = individuals with the same genotype may have different phenotypes

Question 4

what are the four basic tenets of mendel’s first law (of segregation)

Answer 4

1. genes exist in alterative forms (alleles)
2. an organism has two alleles for each gene - one from each parent
3. two alleles segregate during meiosis
4. if two alleles of an organism are different, only one will be fully expressed and the other will be silent (dominant, recessive)

Question 5

mendels first law:

separation of homologous chromosomes during ___________ of meiosis

Answer 5

anaphase 1

Question 6

explain mendels second law (of independent assortment)

Answer 6

the inheritance of one gene does not afferent the inheritance of another gene

Question 7

during ____________ of meiosis, homologous chromosomes pair up to form tetrads and recombination occurs

Answer 7

prophase 1