Inheritance

Question 1

Locus

Answer 1

Chromosomal location defining the position of a gene or DNA sequence

Question 2

Allele

Answer 2

Alternative versions of a gene

Question 3

Genotypes

Answer 3

List of alleles present at one or several loci

Question 4

Phenotypes

Answer 4

characters or traits- observable properties in an organism

Question 5

Homozygous

Answer 5

Both alleles at the locus are the same

Question 6

Heterozygous

Answer 6

Alleles at a locus are different

Question 7

Gene

Answer 7

-Functinal unit of DNA
-Physical and functional unit of heridetary
-It is a determinant or co-determinant of a charcater that is inheritied
-Dos not always encode for proteins

Question 8

Monogenic (Mendelian)

Answer 8

Character programmed by one pair or set of genes at a single locus that are co-inherited
-Expression from both genes required- paricular genotype at locus
-Mendelian characters are recognised by pedigree inheritance patterns

Question 9

OMIM database

Answer 9

Online Mendelian Inheritance in Man database
-Has sequenced genes
-sequences of genes associated with diseases
-Charaters inherited in mendelian pattern with no identified genes

Question 10

Non-Mendelian inheritance

Answer 10

Characters that depend on a large number of genes and environmental factors governed at more than one locus
-Mendelian pedigree not shown

Question 11

Multifactorial In

Answer 11

Non mendelian characteristics
Depend on 2,3 or many loci

Question 12

Oligogenic

Answer 12

Refers to the fact that genetic determination is based on a small nuber of loci

Question 13

Polygenic

Answer 13

Refers to many loci, with each individually small effect
-single primary locus with polygenic background- effect modified by cumulative effect at many loci
-Especially found in psychiatric disorders

Question 14

Dichotomous

Answer 14

Phenotype present or absent
Mendelian Characteristics
eg cystic fibrousis

Question 15

Continous or quantitative

Answer 15

Most human characteristics
-Height or weight- characterisitics that all have but differ to a degree

Question 16

Quantitative trait loci (QTLs)

Answer 16

-At the molecular level-individual genes may have a Mendelian pattern of inheritance
-Character determined in a more complex way
-None-communicable diseases such as metabolic disorders like diabetes or psychiatric diseases- some cases caused in Mendelian way, some based on environment, a majority- multifactoral

Question 17

Mendelian pedigree

Answer 17

This is when a phenotype/character is determined by a variation at a single locus

Question 18

Symbols of pedigree

Answer 18

Question 19

Characteristic Mendelian pedigree patterns

Answer 19

Question 20

Autosomal Domiant Inheritance

Answer 20

Question 21

Autosomal Recessive Inheritance

Answer 21

Question 22

X-linked Recessive Inheritance

Answer 22

Question 23

X-Linked Dominance

Answer 23

Question 24

Y-Linked Inheritance

Answer 24

Question 25

Mitochondrial Inheritance

Answer 25

Question 26

Autosomal recessive carriers

Answer 26

Question 27

Variable expression

Answer 27

Question 28

Types of abnormalities

Answer 28

-Constitutional -Mosaicism -Chimerism

Question 29

Constitutional

Answer 29

-Present in all cells of the body -Inherited or developed very early during embryonic development

Question 30

Mosaicism

Answer 30

-Two or more genetically different cell lines derived from one zygote -Post-Zygotic change in developing embryo

Question 31

Chimerism

Answer 31

Fusion of two zygotes to form single embryo- rare

Question 32

Non-mendelian characters

Answer 32

-Polygenic theory- quantitative traits van be genetically determined -Additive action- Large no. of small independant causes -Shows Gaussian distribution -Conceptua framework for the distribution of a polygenic trait in a population -statistical method