Human Evolution and Genetics Quiz

Modern Taxonomic Groups

• Homo sapiens are the only existing species of the genus Homo
• Y-chromosomal Adam is the most recent common ancestor of all living males
• Mitochondrial Eve is the most recent common ancestor of all living females

Schizophrenia

• Schizophrenia effects about 1% of the world population
• The heritability of schizophrenia is estimated to be as high as 80%
• The genetic component of schizophrenia risk emerged recently in hominid evolution
• People with a higher Neanderthal admixture have less severe positive symptoms
• Individuals with schizophrenia tend to have a lower NeanderScore

Human Genetic Variation

• All humans are 99.9% genetically identical
• The 0.1% variation accounts for all human differences
• The human genome contains 3 billion nucleotides
• Less than 2% of human DNA codes for proteins
• The human genome contains approximately 20,000 genes

Natural Selection

• Natural selection is based on variation, heritability, struggle for existence, and survival and reproductive rates

Twin Studies

• Twin Studies are used to examine the influence of genes and the environment
• Monozygotic twins share 100% of their DNA and the same environment
• Dizygotic twins share 50% of their DNA and the same environment during gestation, birth, and development

Major Depression

• Studies have estimated that the heritability of major depression is between 40% and 50%
• The heritability of severe depression is probably higher
• If a family member has major depression, an individual has a 2-3 times greater risk of developing depression

Human Karyotype

• Humans have 46 chromosomes
• There are 22 pairs of chromosomes from each parent
• One set of sex chromosomes determines gender:
  • Females have XX chromosomes
  • Males have an XY chromosome

Structure of DNA

• The genome is the complete set of genetic information of an organism
• Chromosomes are long strands of DNA wrapped around proteins called histones
• Telomeres are located at the end of each chromosome and protect the DNA during cell division
• Genes are sections of DNA that code for proteins
• Alleles are alternative forms of a gene found at the same locus on a chromosome

Genotype and Phenotype

• Genotype refers to the genetic makeup of an organism
• Phenotype refers to the observable characteristics of an organism, which are influenced by both genes and the environment
• Phenotypes can include features like sensitivity to food reward, likelihood of depression, tendency to persist, and risk of developing diabetes

DNA Processes

• Transcription occurs in the nucleus and involves copying DNA into mRNA
• Translation occurs in the cytoplasm and involves converting mRNA into a protein at the ribosome
• The genetic code is a set of three nucleotides called a codon, which specifies which amino acid will be placed in a protein during translation

Transcription and Splicing

• Transcription involves copying a gene from the DNA template into a primary RNA molecule
• RNA differs from DNA in that it has uracil (U) instead of thymine (T), is shorter in length, and can leave the cell nucleus
• During splicing, introns are removed from the RNA molecule and remain in the nucleus, while exons are exported from the nucleus