MENDELIAN INHERITANCE AND PEDIGREES

Question 1

What is the prevalence and symptoms of Turner’s Syndrome?

Answer 1

1 in 2000 births. Symptoms include retardation of growth, mental retardation, infertility and increased cancer rates. Often have thick necks.

Question 2

Define monohybrid cross.

Answer 2

The crossing of 2 individuals who contain information about different forms of a SINGLE characteristic of interest.

Question 3

Define dihybrid cross.

Answer 3

the crossing of 2 individuals who carry information about different forms of TWO characteristics of interest.

Question 4

What are the 2 conclusions Mendel made from his pea plant experiments?

Answer 4

1. The hereditary determinants of each of the 2 forms of a characteristic were distinct, self-contained units that remained that way during passage from one generation to the next (now known as genes).
2. genes occur in pairs: alternate phenotypes of a characteristic are determined by different forms of a single gene (alleles).

Question 5

Describe alleles.

Answer 5

Different variations of the same gene. The two copies in a gene pair can either be identical or different.
Different alleles occupy the same locus on homologous chromosomes.

Question 6

what are the 3 steps in analysing human inheritance?

Answer 6

1. construction of pedigree
2. assessment of inheritance patterns
3. identify genetic cause: chromosome location, gene or mutation, investigate for other abnormalities

Question 7

Describe autosomal dominant trait/disorders.

Answer 7

Need only one allele in allelic pair to express that trait or disease. Affects both genders equally, and has vertical distribution (occurs in each generation)