(left to right): DENA GROSSENBACHER; MALTE MUELLER/GETTY IMAGES; JENNIFER TAYLOR/CLEVELAND MUSEUM OF NATURAL HISTORY/DALE MORI AND LIZ RUSSELL;

Top stories: The mysterious monkeyflower, same-sex genetics, and Lucy’s likely ancestor

Meet the monkeyflower, a weed that may hold the key to zebra stripes and other biological mysteries

From tiny daisies to giant stinking corpse flowers, floral diversity has long puzzled scientists. Now, researchers are turning to an unusual weed called the monkeyflower, whose explosion of colors and forms, diverse lifestyles, and extraordinary hardiness could make it a perfect all-purpose model plant to help tease apart the mysteries of flower evolution.

Genetics may explain up to 25% of same-sex behavior, giant analysis reveals

People who have had same-sex partners are more likely to have one or more of five DNA markers, according to the largest ever search for genes linked to sexual orientation. But even all the markers taken together cannot predict whether a person is gay, bisexual, or straight. Instead, hundreds or thousands of genes, each with small effects, apparently influence sexual behavior.

Stunning ancient skull shakes up human family tree

A humanoid skull pulled from the sands of northeastern Ethiopia dates back 3.8 million years and is likely Australopithecus anamensis, a hominin long thought to be the direct predecessor of the famed “Lucy” species, A. afarensis. The new fossil, however, could reshuffle that ancient relationship, the authors argue this week in two papers in Nature.

There’s no doubt that Brazil’s fires are linked to deforestation, scientists say

“Dry weather, wind, and heat”—those were the factors that Brazilian Minister of the Environment Ricardo Salles blamed for the rising number of forest fires in the Amazon in a recent tweet. But scientists in Brazil and elsewhere say there is clear evidence that the spike, which has raised concerns around the world, is related to a recent rise in deforestation that many say is partly the result of pro-development policies of the government of Brazilian President Jair Bolsonaro.

Geography of loss—a global look at the uneven toll of suicide

Suicide is a worldwide problem, but its effects are uneven. Although suicide rates are rising in some countries, including the United States, most countries are seeing declines, for reasons that include restrictions on access to lethal means and improved mental health care. These five maps examine how suicide affects different regions of the world, and how those numbers are changing.